Explore topic-wise InterviewSolutions in Class 11.

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37151.

The diameter of one end of a tube is 2 cm and that of another end is 3 cm . Velocity and pressure of water at narrow end are 2ms^(-1)and1.5xx10^(5)Nm^(9-2) respectively . If the height differnce between narrow and broad ends is 2.5 m , find the velocity and pressure of water at the broad end .(Density of water is 1xx10^(3)kgm^(-3)). The narrow end is higher .

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :The <a href="https://interviewquestions.tuteehub.com/tag/narrow-1110745" style="font-weight:bold;" target="_blank" title="Click to know more about NARROW">NARROW</a> end of the flow tube :<br/>`d_(1)=2cm`<br/>`thereforer_(1)=1cm=<a href="https://interviewquestions.tuteehub.com/tag/1xx10-1804645" style="font-weight:bold;" target="_blank" title="Click to know more about 1XX10">1XX10</a>^(-2)m`<br/>`v_(1)=<a href="https://interviewquestions.tuteehub.com/tag/2ms-1837988" style="font-weight:bold;" target="_blank" title="Click to know more about 2MS">2MS</a>^(-1)`<br/>`P_(1)=1.5xx10^(5)Nm^(-2)`<br/>The broad end of the flow tube :<br/>`d_(2)=3cm`<br/>`thereforer_(2)=1.5cm=1.5xx10^(-2)m`<br/>`v_(2)=?,P_(2)=?`<br/>`A_(1)v_(1)=A_(2)v_(2)`<br/>`thereforev_(2)=(A_(1))/(A_(2))v_(1)=(pir_(1)^(2))/(pir_(2)^(2))*v_(1)`<br/>`thereforev_(2)=(r_(1)^(2))/(r_(2)^(2))*v_(1)=((1xx10^(-2))^(2))/((1.5xx10^(-2))^(2))xx2`<br/>`thereforev_(2)=089m//s`<br/>According to Bernoulli.s equation,<br/>`P_(1)+(1)/(2)rhov_(1)^(2)+rhogy_(1)=P_(2)+(1)/(2)rhov_(1)^(2)+rhogy_(2)`<br/>`thereforeP_(2)=P_(1)+(1)/(2)rho(v_(1)^(2)-v_(2)^(2))+rhog(y_(1)-y_(2))`<br/>`=(1.5xx10^(5))+(1)/(2)xx1xx10^(<a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a>)[(2)^(2)-(0.89)^(2)]+1xx10^(3)xx9.8xx2.5`<br/> `thereforeP_(2)=1.76xx10^(5)N//m^(2)`</body></html>
Discussion
37152.

In a standing wave experiment , a 1.2 - kg horizontal rope is fixed in place at its two ends ( x = 0 and x = 2.0 m) and made to oscillate up and down in the fundamental mode , at frequency of 5.0 Hz. At t = 0 , the point at x = 1.0 m has zero displacement and is moving upward in the positive direction of y - axis with a transverse velocity 3.14 m//s. What is the correct expression of the standing wave equation ?

Answer» <html><body><p>`(0.1) sin ( pi//2) x sin (10 pi) t`<br/>`(0.1) sin (pi) x sin (10 pi) t`<br/>`(0.05) sin (pi//2) x cos (10 pi) t`<br/>`(0.04) sin (pi//2) x sin (10 pi) t`</p>Solution :`mu = (1.2)/(2) = 0.6 kg//m` <br/> `<a href="https://interviewquestions.tuteehub.com/tag/n-568463" style="font-weight:bold;" target="_blank" title="Click to know more about N">N</a> = 5 Hz` <br/> `lambda = 2 l = <a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a> m` <br/> `V = n lambda = 5 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 4 = 20 m//s` <br/> Using `v = sqrt((T)/(mu))` <br/> `T = 20^(2) xx 0.6 = 240 N` <br/> `((delta y)/( delta t))_(max) = 3.14 m//s` <br/> `( 2 A)omega = 3.14` <br/> Amplitude `2A = (3.14)/(2 xx (3.14) xx 5) = 0.1 m` <br/> <a href="https://interviewquestions.tuteehub.com/tag/equation-974081" style="font-weight:bold;" target="_blank" title="Click to know more about EQUATION">EQUATION</a> of standing wave is <br/> `y = (0.1) sin (pi)/(2) s sin (10 pi) t`</body></html>
Discussion
37153.

Aluminium wire of length 2.2 m and a Iron wire of length 1.6 m, both of diameter 3.0 mm, are connected end to end. When stretched by a load, the net elongation is found to be 0.70 mm. Obtain the load applied.Young's modulus of aluminium Y_(Al) =70 xx 10 ^(9) Nm ^(-2) Young's modulus of iron Y_(F)=120 xx 10 ^(9) Nm ^(-2)

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :Appliec <a href="https://interviewquestions.tuteehub.com/tag/load-11593" style="font-weight:bold;" target="_blank" title="Click to know more about LOAD">LOAD</a> `<a href="https://interviewquestions.tuteehub.com/tag/f-455800" style="font-weight:bold;" target="_blank" title="Click to know more about F">F</a> = 111.3N`</body></html>
Discussion
37154.

Moment of inertia does not depend on

Answer» <html><body><p>mass distribution of <a href="https://interviewquestions.tuteehub.com/tag/body-900196" style="font-weight:bold;" target="_blank" title="Click to know more about BODY">BODY</a> <br/>torque <br/>shape of the body<br/>the <a href="https://interviewquestions.tuteehub.com/tag/position-1159826" style="font-weight:bold;" target="_blank" title="Click to know more about POSITION">POSITION</a> of axis of <a href="https://interviewquestions.tuteehub.com/tag/rotation-11281" style="font-weight:bold;" target="_blank" title="Click to know more about ROTATION">ROTATION</a> </p>Solution :Moment of inertia does not <a href="https://interviewquestions.tuteehub.com/tag/depend-948478" style="font-weight:bold;" target="_blank" title="Click to know more about DEPEND">DEPEND</a> on torque .</body></html>
Discussion
37155.

A U-tube is supoorted with its limbs vertical and is partly filled with water. If internal diameter of the limbs are 1xx10^(-2)m and 1xx10^(-4) m respectively what will be the difference in heights of water columns in the two limbs (Surface tension of water is 0.07Nm^(-1))

Answer» <html><body><p></p>Solution :Surface <a href="https://interviewquestions.tuteehub.com/tag/tension-1241727" style="font-weight:bold;" target="_blank" title="Click to know more about TENSION">TENSION</a> `S=0.07Nm^(-1)` <br/> Densith `rho=1000 kgm^(-3),<a href="https://interviewquestions.tuteehub.com/tag/g-1003017" style="font-weight:bold;" target="_blank" title="Click to know more about G">G</a>=9,8ms^(-2)` <br/> Angle of contact `theta=0^(@)` <br/> <a href="https://interviewquestions.tuteehub.com/tag/radius-1176229" style="font-weight:bold;" target="_blank" title="Click to know more about RADIUS">RADIUS</a> `r_(1)=0.5xx10^(-2)m, ` Radius `r_(2)=0.5xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a>)m` <br/>Let `h_(1)` be the height of water in the limb of radius `r_(1)` <br/> Then `h_(1)=(2Scos theta)/(r_(1)rho g)=(2xx0.07xxcos 0^(@))/(0.5xx10^(-2)xx1000xx9.8)m` <br/> `=2.86xx10^(-3)m` <br/> similarly `h_(2)=2.86xx10^(-1)m` <br/> Difference in heights <br/> `=h_(2)-h_(1)=2.86xx10^(-1)m-2.86xx10^(-3)m` <br/> `=(0.286-0.00286)m=0.283m`</body></html>
Discussion
37156.

In a two dimensional motion,instantaneous speed v_(0) is a positive constant.Then which of the following are necessarily true?

Answer» <html><body><p>The average velocity is not zero at any <a href="https://interviewquestions.tuteehub.com/tag/time-19467" style="font-weight:bold;" target="_blank" title="Click to know more about TIME">TIME</a>. <br/>Average <a href="https://interviewquestions.tuteehub.com/tag/acceleration-13745" style="font-weight:bold;" target="_blank" title="Click to know more about ACCELERATION">ACCELERATION</a> must always vanish. <br/>Displacements is <a href="https://interviewquestions.tuteehub.com/tag/equal-446400" style="font-weight:bold;" target="_blank" title="Click to know more about EQUAL">EQUAL</a> time intervals are equal. <br/>Equal path lengths are traversed in equal intervals. </p>Solution :In two dimensional motion, if instanttaneous speed is a positive constant then equal path lengths are traversed in equal intervals of time.</body></html>
Discussion
37157.

A train standing at the outer signal of a railway station blows a whistle of frequency 400Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10 ms^(-1). (b) recedes from the platform with a speed of 10ms^(-1) ? (ii) What is the speed of sound in each case? The speed of sound in still air can be taken as 340ms^(-1).

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :(i) (a) 412Hz, (<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a>) 389Hz, (ii) `<a href="https://interviewquestions.tuteehub.com/tag/340-308308" style="font-weight:bold;" target="_blank" title="Click to know more about 340">340</a> <a href="https://interviewquestions.tuteehub.com/tag/ms-549331" style="font-weight:bold;" target="_blank" title="Click to know more about MS">MS</a>^(-1)` in each case</body></html>
Discussion
37158.

A bottle whose volume is 0.45 xx 10^(-3) m^(3) is sunk mouth downwards below the surface of water in a tank. How far must it be sunk so that 0.75 xx 10^(-4) m^(3)of water may run up into bottle ? The atmospheric pressure =10^(5) Nm^(-2) and density of water =1000 kg m^(-3)

Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :10.34 m</body></html>
Discussion
37159.

The relation between the slope of isothermal curve and slope of adiabatic curve is

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/slope-15649" style="font-weight:bold;" target="_blank" title="Click to know more about SLOPE">SLOPE</a> of <a href="https://interviewquestions.tuteehub.com/tag/adiabatic-849856" style="font-weight:bold;" target="_blank" title="Click to know more about ADIABATIC">ADIABATIC</a> curve `= gamma` times slope of <a href="https://interviewquestions.tuteehub.com/tag/isothermal-520014" style="font-weight:bold;" target="_blank" title="Click to know more about ISOTHERMAL">ISOTHERMAL</a> curve<br/>slope of isothermal curve `= gamma` times slope of adiabatic curve<br/>slope of adiabatic curve `= gamma^(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)` times slope of isothermal curve <br/>slope of isothermal curve `= gamma^(2)` times slope of adiabatic curve</p>Answer :A</body></html>
Discussion
37160.

As a spherical wave propagates, ……….. .

Answer» <html><body><p>the wave <a href="https://interviewquestions.tuteehub.com/tag/intensity-1047474" style="font-weight:bold;" target="_blank" title="Click to know more about INTENSITY">INTENSITY</a> <a href="https://interviewquestions.tuteehub.com/tag/remains-621920" style="font-weight:bold;" target="_blank" title="Click to know more about REMAINS">REMAINS</a> <a href="https://interviewquestions.tuteehub.com/tag/constant-930172" style="font-weight:bold;" target="_blank" title="Click to know more about CONSTANT">CONSTANT</a> <br/>the wave intensity <a href="https://interviewquestions.tuteehub.com/tag/decrease-946104" style="font-weight:bold;" target="_blank" title="Click to know more about DECREASE">DECREASE</a> as the inverse of the distance from the source <br/> the wave intensity decreases as the inverse <a href="https://interviewquestions.tuteehub.com/tag/square-650836" style="font-weight:bold;" target="_blank" title="Click to know more about SQUARE">SQUARE</a> of the distance from the source. <br/>The wave intensity decreases as the inverse cube of the distance from the source. </p>Solution :The wave intensity decreases as the inverse square of the distance from the source.</body></html>
Discussion
37161.

A satellite is revolving in a circular orbit of radius R. Ratio of KE and its PE is (only magnitude )

Answer» <html><body><p> `1:4`<br/> `2:1`<br/>`3:2`<br/>`1:2`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html>
Discussion
37162.

Letthe speed of the planet attheperihelion pin be vPand the Sun-planet distance SP be r_(P). Relate {r_(P), v_(P)} to the corresponding quantities at the aphelion {r_(A), v_(A)}. Will the planet take equal times to traverse BAC and CPB ?

Answer» <html><body><p></p>Solution : The <a href="https://interviewquestions.tuteehub.com/tag/magnitude-1083080" style="font-weight:bold;" target="_blank" title="Click to know more about MAGNITUDE">MAGNITUDE</a> of the angular <a href="https://interviewquestions.tuteehub.com/tag/momentum-1100588" style="font-weight:bold;" target="_blank" title="Click to know more about MOMENTUM">MOMENTUM</a> at P is `L_(p)` =`m_(p) r_(p) v_(p)`, since inspection tells us that rp and vp are mutually perpendicular. Similarly,` L_(A) = m_(p) r_(A) v_(A)`. From angular momentum conservation<br/> `m_(p) r_(p) v_(p) = m_(p) r_(A) v_(A)`<br/> or `(v_(p))/(v_(A)) = (r_(A))/(r_(p))`<br/> since `r_(A) gt r_(p), v_(p) gt v_(A).` <br/> the area SBAC bounded by the ellipse and the <a href="https://interviewquestions.tuteehub.com/tag/radius-1176229" style="font-weight:bold;" target="_blank" title="Click to know more about RADIUS">RADIUS</a> vectors SB and SC is larger than SBPC in From Kepler’s second law, equal <a href="https://interviewquestions.tuteehub.com/tag/areas-883934" style="font-weight:bold;" target="_blank" title="Click to know more about AREAS">AREAS</a> are swept in equal times. Hence the planet will take a longer time to traverse BAC than CPB.</body></html>
Discussion
37163.

Which of the following following expressions correspons to simple harmonicmotion along a straightline, where x is the displacement and a,b,c are positive constants?

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/bx-906513" style="font-weight:bold;" target="_blank" title="Click to know more about BX">BX</a>^(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)`<br/>`a+bx-cx^(2)`<br/>`-bx^(2)`<br/>`a-bx+cx^(2)`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a></body></html>
Discussion
37164.

Derive an expression for the elastic energy stored per unit volume of a wire.

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :When a body is stretched, work is done against the <a href="https://interviewquestions.tuteehub.com/tag/restoring-1187260" style="font-weight:bold;" target="_blank" title="Click to know more about RESTORING">RESTORING</a> force (internal force). This work done is stored in the body in the form of elastic energy. Consider a wire whose un-stretch length is L and area of cross section is A. Let a force produce an extension l and further assume that the elastic limit of the wire has not been exceeded and there is no loss in energy.Then , the work done by the force F is equal to the energy gained by the wire. <br/> The work done in stretching the wire by `dl, dW = F dl` <br/> The total work done in stretching the wire from 0 to l is <br/> `W = int_(0)^(l) F dl "" ....(1)` <br/> From Young.s modulus of elasticity, <br/> `Y = F/A xx L/l implies F = (YAl)/L "" ....(2)` <br/> <a href="https://interviewquestions.tuteehub.com/tag/substituting-1231652" style="font-weight:bold;" target="_blank" title="Click to know more about SUBSTITUTING">SUBSTITUTING</a> equation (2) in equation (1), we <a href="https://interviewquestions.tuteehub.com/tag/get-11812" style="font-weight:bold;" target="_blank" title="Click to know more about GET">GET</a> <br/> `W = int_(0)^(l) (YA l)/(L) dl` <br/> Since, l is the dummy variable in the <a href="https://interviewquestions.tuteehub.com/tag/intergration-2743881" style="font-weight:bold;" target="_blank" title="Click to know more about INTERGRATION">INTERGRATION</a>, we can change l to l. (not in limits), therefore <br/> `W = int_(0)^(l) (YAl^.)/(L) dl. = (YA)/L ((l.^2)/(2))_0^l = (YA)/L (l^2)/2 = 1/2 ((YAl)/(L)) l=1/2 Fl` <br/> `W = 1/2 Fl` = Elastic potential energy <br/> Energy per unit volume is called energy density <br/> `u = ("Elastic potential energy")/("Volume") = (1/2 Fl)/(AL)` <br/> `1/2 F/A l/L = 1/2 ("Stress" xx "Strain")`.</body></html>
Discussion
37165.

A lead bullet of mass 21 g travelling at a speed of 100m//s comes to rest in a wooden block . If no heat is taken away by the wood , the rise in temperature of the bullet in the wood nearly is (specified heat of lead =30 cal//kg^(@)C )

Answer» <html><body><p></p>Solution :Kinetic energy of the <a href="https://interviewquestions.tuteehub.com/tag/bullet-403823" style="font-weight:bold;" target="_blank" title="Click to know more about BULLET">BULLET</a>=heat gained by the bullet `1/<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a> mv^(2) = msDeltat` <br/> `Delta t =(v^(2))/(<a href="https://interviewquestions.tuteehub.com/tag/2s-301125" style="font-weight:bold;" target="_blank" title="Click to know more about 2S">2S</a>) = ((100^(2)))/(2xx0.03xx4.2xx1000) = 39.68^(@)C`</body></html>
Discussion
37166.

The oxygen molecule has a mass of 5.30 × 10^(-26) kg and a moment of inertia of 1.94×10^(-46) kg m^(2) about an axis through its centre perpendicular to the lines joining the two atoms. Suppose the mean speed of such a molecule in a gas is 500 m/s and that its kinetic energy of rotation is two thirds of its kinetic energy of translation. Find the average angular velocity of the molecule.

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :`6.75xx10^(<a href="https://interviewquestions.tuteehub.com/tag/12-269062" style="font-weight:bold;" target="_blank" title="Click to know more about 12">12</a>)" <a href="https://interviewquestions.tuteehub.com/tag/rad-1175618" style="font-weight:bold;" target="_blank" title="Click to know more about RAD">RAD</a> s"^(-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)`</body></html>
Discussion
37167.

A ball of mass m is dropped from a heighth on a platform fixed at the top of a vertical spring, as shown in figure. The platform is depressed by a distance x. Then the spring constant is 

Answer» <html><body><p>`(<a href="https://interviewquestions.tuteehub.com/tag/mg-1095425" style="font-weight:bold;" target="_blank" title="Click to know more about MG">MG</a>)/((h + x))`<br/>`(mg)/((h + 2x))`<br/>`(2mg(h + x))/(x^2)`<br/>`(mg)/((2h + x)`</p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :Loss in potential energy of the <a href="https://interviewquestions.tuteehub.com/tag/ball-891849" style="font-weight:bold;" target="_blank" title="Click to know more about BALL">BALL</a> = `mg(h + x)` <br/> Gain in elastic potential energy of the spring = `1/2 kx^2` <br/> According to the <a href="https://interviewquestions.tuteehub.com/tag/law-184" style="font-weight:bold;" target="_blank" title="Click to know more about LAW">LAW</a> of conservation of mechanical energy <br/> `mg(h + x) = 1/2 kx^2 " or " k = (2mg (h + x))/(x^2)` .</body></html>
Discussion
37168.

A body projected vertically upwards from the surface of the earth with a velocity equal to 1//3^(rd) of the escape velocity. The height reached by it if the radius of the earth is 6400 km is

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/3200-307562" style="font-weight:bold;" target="_blank" title="Click to know more about 3200">3200</a> <a href="https://interviewquestions.tuteehub.com/tag/km-1064498" style="font-weight:bold;" target="_blank" title="Click to know more about KM">KM</a> <br/><a href="https://interviewquestions.tuteehub.com/tag/7200-334458" style="font-weight:bold;" target="_blank" title="Click to know more about 7200">7200</a> km <br/><a href="https://interviewquestions.tuteehub.com/tag/6400-330890" style="font-weight:bold;" target="_blank" title="Click to know more about 6400">6400</a> km<br/>800 km </p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :D</body></html>
Discussion
37169.

A particle executes SHMof period 22 second and amplitude 10 cm. Find the distance it travels in 3.5 second starting from the point of zero displacement.

Answer» <html><body><p></p>Solution :Amplitude of the particle = <a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a> cm=0.01 m, Time <br/> period `t=22s` and `phi_(0)=0` <br/> The angular velocity `<a href="https://interviewquestions.tuteehub.com/tag/omega-585625" style="font-weight:bold;" target="_blank" title="Click to know more about OMEGA">OMEGA</a>=(2pi)/T=(2xx22)/(7xx22)=2/7` rad/s <br/> The equation for displacement of the particle is <br/> `x=Asin (omega t+phi)=0.10sin(2/7t)` <br/> when `t=3.5s=7/2`s the distance it travels <a href="https://interviewquestions.tuteehub.com/tag/becomes-1994370" style="font-weight:bold;" target="_blank" title="Click to know more about BECOMES">BECOMES</a> equal to the displacement because the <a href="https://interviewquestions.tuteehub.com/tag/gives-1007647" style="font-weight:bold;" target="_blank" title="Click to know more about GIVES">GIVES</a> time is less than `T//4`. <br/> `:. x=0.10sin(2/7xx7/2)=0.10sin(1)` <br/> `=0.10sin (57^(@)17.) ( :. 1"radian"=57^(@)17.)` <br/> `=0.10xx0.8414=0.8414m`</body></html>
Discussion
37170.

A circular disc of mass 10 kg is suspended by a wire attached to its centre. The wire is twisted by rotating the disc and released. The period of torsional oscillations is found to be 1.5 s. The radius of the disc is 15 cm. Determine the torsional spring constant of the wire. (Torsional spring constant a is defined by the relation J = –alphatheta , where J is the restoring couple and q the angle of twist).

Answer» <html><body><p></p>Solution :Hint: The time period of a torsional <a href="https://interviewquestions.tuteehub.com/tag/pendulum-1149901" style="font-weight:bold;" target="_blank" title="Click to know more about PENDULUM">PENDULUM</a> is given by `T=2pisqrt(l/(<a href="https://interviewquestions.tuteehub.com/tag/alpha-858274" style="font-weight:bold;" target="_blank" title="Click to know more about ALPHA">ALPHA</a>))`. where I is the moment of inertia about the axis of rotation. In our case `I=1/2MR^(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)`, where M is the mass of the <a href="https://interviewquestions.tuteehub.com/tag/disk-955870" style="font-weight:bold;" target="_blank" title="Click to know more about DISK">DISK</a> and <a href="https://interviewquestions.tuteehub.com/tag/r-611811" style="font-weight:bold;" target="_blank" title="Click to know more about R">R</a> its radius. Substituting the given values, `alpha=2.0Nmrad^(-1)`</body></html>
Discussion
37171.

A sting breaks under a load of 4.8 kg A mass of 0.5 kg is attached to one end tothe string 2malong and is ratated in a horizontal circle caculate the greatest number of revolutions that the mass can make without breaking the string

Answer» <html><body><p></p>Solution :Given`m=0.5 kg` <br/> `r=2 m` <br/> `g=9.8ms^(-2)` <br/> Themaximumtensionthat the stringcanwithstand <br/> `F=4.8 kg wt=4.8xx 9.8 <a href="https://interviewquestions.tuteehub.com/tag/n-568463" style="font-weight:bold;" target="_blank" title="Click to know more about N">N</a>` <br/><a href="https://interviewquestions.tuteehub.com/tag/let-11597" style="font-weight:bold;" target="_blank" title="Click to know more about LET">LET</a> themaximum <a href="https://interviewquestions.tuteehub.com/tag/number-582134" style="font-weight:bold;" target="_blank" title="Click to know more about NUMBER">NUMBER</a> of revolutions persecond=v<br/> Now F = `mr epsilon^(2)= mr (2 pi v)^(2) = <a href="https://interviewquestions.tuteehub.com/tag/4pi-1882352" style="font-weight:bold;" target="_blank" title="Click to know more about 4PI">4PI</a>^(2) mrv^(2)` <br/> or `v^(2)=(F )/(4pi^(2)mr)` <br/> `=(4.8 xx 9.8)/( 4xx 9.8 xx 0.5 xx 2) =1.215` <br/> or `v = <a href="https://interviewquestions.tuteehub.com/tag/sqrt-1223129" style="font-weight:bold;" target="_blank" title="Click to know more about SQRT">SQRT</a>(1.215 )= 1.102 rps` <br/> `=1.102 xx 60 =66 .13 rpm`</body></html>
Discussion
37172.

A cyclist is riding on a cycle with speed v and while negotiating a circular path of radius r, he leans at an angle theta with the ground. Then, what will be the value of tantheta?

Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :`(<a href="https://interviewquestions.tuteehub.com/tag/rg-1188560" style="font-weight:bold;" target="_blank" title="Click to know more about RG">RG</a>)/(<a href="https://interviewquestions.tuteehub.com/tag/v-722631" style="font-weight:bold;" target="_blank" title="Click to know more about V">V</a>^(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>))`</body></html>
Discussion
37173.

A rectangular box lies on a rough inclined surface. The coefficient of friction between the surface and the box is mu. Let the mass of the box be m. (a) At what angle of inclination 0 of the plane to the horizontal will the box just start to slide down the plane ? (b) What is the force acting on the box down the plane, if the angle of inclination of the plane is increased to a gt theta (c) What is the force needed to be applied upwards along the plane to make the box either remain stationary or just move up with uniform speed ? (d) What is the force needed to be applied upwards along the plane to make the box move up the plane with acceleration a ?

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :Considerdiagram <a href="https://interviewquestions.tuteehub.com/tag/shownin-1206577" style="font-weight:bold;" target="_blank" title="Click to know more about SHOWNIN">SHOWNIN</a> figure <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/KPK_AIO_PHY_XI_P1_C05_E04_041_S01.png" width="80%"/> <br/> (a ) For bxjuststartsto sliding downslope<br/> `<a href="https://interviewquestions.tuteehub.com/tag/f-455800" style="font-weight:bold;" target="_blank" title="Click to know more about F">F</a> = mg sin theta` <br/> `N=m g <a href="https://interviewquestions.tuteehub.com/tag/cos-935872" style="font-weight:bold;" target="_blank" title="Click to know more about COS">COS</a> theta` <br/> `(f )/(N )= tan theta` <br/> `<a href="https://interviewquestions.tuteehub.com/tag/mu-566056" style="font-weight:bold;" target="_blank" title="Click to know more about MU">MU</a> = tan theta` <br/>`theta= tan ^(-1)(mu)` <br/> ( b)Whenangle ofinclinationincreasedto <br/> `alpha gttheta` <br/> Resultantforcebe `F_(1)` <br/> `F_(1)= mgsin alpha- f`<br/> (c ) Tokeepboxstationaryor movingwithuniformspeedupwardforceir requiredHerefrictionforcewouldbed indownwarddirection <br/> (d ) Whenbox isto bemovedwithaccelerationa upwardalong theplanenet forcebe `F_(3)` <br/>frictionwouldbe indownwarddirection <br/> `F_(3)= mg (sinalpha+ mu cos alpha )+ ma`</body></html>
Discussion
37174.

Springs of spring constants K, 2K, 4K, 8K ...... 2048 K are connected in series. A mass 'm' is attached to one end the system is allowed to oscillate. Its time period is approximately

Answer» <html><body><p>`2pi <a href="https://interviewquestions.tuteehub.com/tag/sqrt-1223129" style="font-weight:bold;" target="_blank" title="Click to know more about SQRT">SQRT</a>((m)/(<a href="https://interviewquestions.tuteehub.com/tag/2k-300402" style="font-weight:bold;" target="_blank" title="Click to know more about 2K">2K</a>))`<br/>`2pi sqrt((<a href="https://interviewquestions.tuteehub.com/tag/2m-300757" style="font-weight:bold;" target="_blank" title="Click to know more about 2M">2M</a>)/(K))`<br/>`2pi sqrt((m)/(4K))`<br/>`2pi sqrt((<a href="https://interviewquestions.tuteehub.com/tag/4m-318788" style="font-weight:bold;" target="_blank" title="Click to know more about 4M">4M</a>)/(K))`</p>Answer :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html>
Discussion
37175.

The momentumof a body increased doubled .What is the percentage of increment in its kinetic energy ?

Answer» <html><body><p></p>Solution :`K = 1/mv^(2) = (p^(2))/(<a href="https://interviewquestions.tuteehub.com/tag/2m-300757" style="font-weight:bold;" target="_blank" title="Click to know more about 2M">2M</a>) "" …(1)`<br/> `K = (p^(2))/(2m) ""….(2)`<br/> `p. =2p ` <br/> ` :. K = (4p^(2))/(2m)`<br/> ` :. K . = <a href="https://interviewquestions.tuteehub.com/tag/4k-318773" style="font-weight:bold;" target="_blank" title="Click to know more about 4K">4K</a> `<br/> Increase in <a href="https://interviewquestions.tuteehub.com/tag/kinetic-533291" style="font-weight:bold;" target="_blank" title="Click to know more about KINETIC">KINETIC</a> energy= `(DeltaK)/K xx100` <br/> `= (3K)/K <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 100` <br/> = <a href="https://interviewquestions.tuteehub.com/tag/300-305868" style="font-weight:bold;" target="_blank" title="Click to know more about 300">300</a> %</body></html>
Discussion
37176.

In the figure (i), (ii) and (iii) shown the objects, A,B and C are of same mass. String, spring and pulley are massless. C strikes B with velocity u in each case and stricks to it. The ratio of velocity of B in case (i) to (ii) to (iii) is-

Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html>
Discussion
37177.

Among the following which are the examples of SHM?Oscillation of simple pendulum

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/oscillation-1139998" style="font-weight:bold;" target="_blank" title="Click to know more about OSCILLATION">OSCILLATION</a> of <a href="https://interviewquestions.tuteehub.com/tag/simple-1208262" style="font-weight:bold;" target="_blank" title="Click to know more about SIMPLE">SIMPLE</a> <a href="https://interviewquestions.tuteehub.com/tag/pendulum-1149901" style="font-weight:bold;" target="_blank" title="Click to know more about PENDULUM">PENDULUM</a></body></html>
Discussion
37178.

When a man running on a levelground increases his speed by 4ms^(-2), if his kinetic energy increases by 125% his initial velocity is

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a> ms^(-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)`<br/>`8 ms^(-1)`<br/>`2ms^(-1)`<br/>`6 ms^(-1)`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html>
Discussion
37179.

A block of mass .m. is pulled by a force .F. on a level surface through a distance .S., then

Answer» <html><body><p>The <a href="https://interviewquestions.tuteehub.com/tag/work-20377" style="font-weight:bold;" target="_blank" title="Click to know more about WORK">WORK</a> done on the body against <a href="https://interviewquestions.tuteehub.com/tag/gravitational-476409" style="font-weight:bold;" target="_blank" title="Click to know more about GRAVITATIONAL">GRAVITATIONAL</a> <a href="https://interviewquestions.tuteehub.com/tag/force-22342" style="font-weight:bold;" target="_blank" title="Click to know more about FORCE">FORCE</a> is zero<br/>The work done on the body against gravitational force is mgS<br/>The work done on the body against its weight is F.S <br/>The work done on the body against friction is mgS</p>Answer :A</body></html>
Discussion
37180.

Explain various types of friction suggest a few methodsto reduce friction

Answer» <html><body><p></p>Solution :There are two types of Friction: <br/> (i) Static Friction: Static friction is the force which opposes the initiation of motion of an object on the surface. The magnitude of static frictional force `f_s`lies between <br/> `0 <a href="https://interviewquestions.tuteehub.com/tag/lt-537906" style="font-weight:bold;" target="_blank" title="Click to know more about LT">LT</a>= f_s lt= mu_s N` <br/>where ,`mu_s` - coefficient of static friction <br/>N - Normal force<br/>Kinetic friction: The frictional force exerted by the surface when an object slides as kinetic friction. Also called as <a href="https://interviewquestions.tuteehub.com/tag/sliding-1211847" style="font-weight:bold;" target="_blank" title="Click to know more about SLIDING">SLIDING</a> friction or <a href="https://interviewquestions.tuteehub.com/tag/dynamic-11476" style="font-weight:bold;" target="_blank" title="Click to know more about DYNAMIC">DYNAMIC</a> friction, <br/>`f_k = mu_ k N` <br/> where `mu_k`- the coefficient of kinetic friction <br/>N - Normal force exerted by the surface on the object <br/>Methods to reduce friction: Friction can be reduced <br/>(i) By using lubricants (ii) By using Ball bearings (iii) By polishing (<a href="https://interviewquestions.tuteehub.com/tag/iv-501699" style="font-weight:bold;" target="_blank" title="Click to know more about IV">IV</a>) By streamlining</body></html>
Discussion
37181.

A body of mass m_1, projected vertically upwards with an initial velocity 'u' reaches a maximum height 'h'. Another body of mass m_2is projected along an inclined plane making an angle 30^@with the horizontal and with speed 'u'. The maximum distance travelled along the incline is

Answer» <html><body><p>2h<br/>h<br/>h/2<br/>h/4</p>Answer :A</body></html>
Discussion
37182.

Two persons pull a rope by its two ends, exerting equal but opposite forces F. In another situation, one end of the rope is tied to a rigid support and a person pulls it with a force of 2F. In which case will the tension in the be greater ?

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/tension-1241727" style="font-weight:bold;" target="_blank" title="Click to know more about TENSION">TENSION</a> in the rope in the <a href="https://interviewquestions.tuteehub.com/tag/second-1197322" style="font-weight:bold;" target="_blank" title="Click to know more about SECOND">SECOND</a> <a href="https://interviewquestions.tuteehub.com/tag/case-910082" style="font-weight:bold;" target="_blank" title="Click to know more about CASE">CASE</a> will be greater i.e., T. = 2F, whereas the tension, in the <a href="https://interviewquestions.tuteehub.com/tag/first-461760" style="font-weight:bold;" target="_blank" title="Click to know more about FIRST">FIRST</a> case is T = F.<br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/CHY_DMB_PHY_XI_P1_U03_C01_E02_012_S01.png" width="80%"/></body></html>
Discussion
37183.

An artificial satellite revolves around the earth, remaining close to the surface of the earth, Show that its time period is T = 2pi sqrt(R_e/g)

Answer» <html><body><p></p>Solution :`<a href="https://interviewquestions.tuteehub.com/tag/implies-1037962" style="font-weight:bold;" target="_blank" title="Click to know more about IMPLIES">IMPLIES</a>` The necessary <a href="https://interviewquestions.tuteehub.com/tag/centripetal-415325" style="font-weight:bold;" target="_blank" title="Click to know more about CENTRIPETAL">CENTRIPETAL</a> force for satellite of mass m revolves around the earth is provided by <a href="https://interviewquestions.tuteehub.com/tag/gravitational-476409" style="font-weight:bold;" target="_blank" title="Click to know more about GRAVITATIONAL">GRAVITATIONAL</a> force. <br/> `:.`Centripetal force = Gravitational force,<br/> Subsituting this in equation (1), <br/> `:. (mv^<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)/R_e =mg ""...(1)` <br/> but `v= R_eomega` <br/> `:. v = R_e (2pi)/T"" [ :. omega =(2pi)/T]`<br/> `:.` Subsituting this in equation (1), <br/> `:. (R_e^2xx4pi^2)/(R_e.T^2)=g` <br/> `:. T^2= <a href="https://interviewquestions.tuteehub.com/tag/4pi-1882352" style="font-weight:bold;" target="_blank" title="Click to know more about 4PI">4PI</a> ^(2) R_e/g "" :. T = 2pi sqrt((R_e)/g)`</body></html>
Discussion
37184.

The length of a cyclinder is measured as 5 cm usinga verniercalipersof least count 0.1mm. The percentage error in the measured length is nerarly

Answer» <html><body><p>`0.5%`<br/>`2%`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/20-287209" style="font-weight:bold;" target="_blank" title="Click to know more about 20">20</a>%`<br/>`0.2%`</p>Solution :`(<a href="https://interviewquestions.tuteehub.com/tag/delta-947703" style="font-weight:bold;" target="_blank" title="Click to know more about DELTA">DELTA</a> <a href="https://interviewquestions.tuteehub.com/tag/l-535906" style="font-weight:bold;" target="_blank" title="Click to know more about L">L</a>)/(l) <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 100`</body></html>
Discussion
37185.

Statement 1: In process of photoelectric emission, all emitted electrons do not have same kinetic energy. Statement 2: If radiation falling on photosensitive surface of a metal consists of different wavelengths, then energy acquired by electrons absorbing photons of different wavelengths shall be different.

Answer» <html><body><p>Statement-1 is true, Statement-2: is true, Statement-2 is a correct <a href="https://interviewquestions.tuteehub.com/tag/explanation-455162" style="font-weight:bold;" target="_blank" title="Click to know more about EXPLANATION">EXPLANATION</a> for Statement-1.<br/>Statement-1 is true, Statement-2: is true, Statement-2 is NOT a correct explanation for Statement-1.<br/>Statement-1 is true but statement-2 is false<br/>Statement-1 is false, Statement-2 is true</p>Solution :Both statement 1 and 2 are true, but <a href="https://interviewquestions.tuteehub.com/tag/even-976335" style="font-weight:bold;" target="_blank" title="Click to know more about EVEN">EVEN</a> it radiation of single wavelengthis incident on <a href="https://interviewquestions.tuteehub.com/tag/photosensitive-2221004" style="font-weight:bold;" target="_blank" title="Click to know more about PHOTOSENSITIVE">PHOTOSENSITIVE</a> surface, electrons of different KE will be emitted.</body></html>
Discussion
37186.

Animals curl into a ball when it is very cold.Why?

Answer» <html><body><p></p>Solution :Energy rediated is proprotional to the surface area of the body.They curl into a ball so as to <a href="https://interviewquestions.tuteehub.com/tag/decrease-946104" style="font-weight:bold;" target="_blank" title="Click to know more about DECREASE">DECREASE</a> the surface area and thereby <a href="https://interviewquestions.tuteehub.com/tag/reduce-1181332" style="font-weight:bold;" target="_blank" title="Click to know more about REDUCE">REDUCE</a> the loss of heat by <a href="https://interviewquestions.tuteehub.com/tag/radiation-1175811" style="font-weight:bold;" target="_blank" title="Click to know more about RADIATION">RADIATION</a>.</body></html>
Discussion
37187.

The above question 26, the normal force acting, betweent :

Answer» <html><body><p>wedge and incline <a href="https://interviewquestions.tuteehub.com/tag/plane-1155510" style="font-weight:bold;" target="_blank" title="Click to know more about PLANE">PLANE</a> is `Mg cos <a href="https://interviewquestions.tuteehub.com/tag/theta-1412757" style="font-weight:bold;" target="_blank" title="Click to know more about THETA">THETA</a>`<br/>m and wedge is zero<br/>m and wedge is zero<br/>m and wedge is `mg sin theta`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :a,<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html>
Discussion
37188.

What is the necessary condition for the formation of stationary waves ?

Answer» <html><body><p></p>Solution :A stationary <a href="https://interviewquestions.tuteehub.com/tag/wave-22399" style="font-weight:bold;" target="_blank" title="Click to know more about WAVE">WAVE</a> cant' be formed from two independent waves <a href="https://interviewquestions.tuteehub.com/tag/travelling-1426809" style="font-weight:bold;" target="_blank" title="Click to know more about TRAVELLING">TRAVELLING</a> in a <a href="https://interviewquestions.tuteehub.com/tag/medium-1092763" style="font-weight:bold;" target="_blank" title="Click to know more about MEDIUM">MEDIUM</a> in opposite directions. Acutually stationary wave in <a href="https://interviewquestions.tuteehub.com/tag/produced-592947" style="font-weight:bold;" target="_blank" title="Click to know more about PRODUCED">PRODUCED</a> when a progressive wave and its reflected waves are <a href="https://interviewquestions.tuteehub.com/tag/superposed-7715918" style="font-weight:bold;" target="_blank" title="Click to know more about SUPERPOSED">SUPERPOSED</a>. It can be produced in a finite medium which has its boundaries.</body></html>
Discussion
37189.

Statement I : The maximum speed at which a car can turn on level curve of radius 40 m, is 11 m/s ,  = 0.3 . Statement II : v = μRg   = Rg v2 = 40 10 11 11   = 0.3.

Answer» <html><body><p> If both <a href="https://interviewquestions.tuteehub.com/tag/statement-16478" style="font-weight:bold;" target="_blank" title="Click to know more about STATEMENT">STATEMENT</a>- I and Statement- <a href="https://interviewquestions.tuteehub.com/tag/ii-1036832" style="font-weight:bold;" target="_blank" title="Click to know more about II">II</a> are <a href="https://interviewquestions.tuteehub.com/tag/true-713260" style="font-weight:bold;" target="_blank" title="Click to know more about TRUE">TRUE</a>, and Statement - II is the <a href="https://interviewquestions.tuteehub.com/tag/correct-409949" style="font-weight:bold;" target="_blank" title="Click to know more about CORRECT">CORRECT</a> explanation of Statement– I.<br/> If both Statement - I and Statement - II are true but Statement - II is not the correct explanation of Statement – I<br/> If Statement - I is true but Statement - II is <a href="https://interviewquestions.tuteehub.com/tag/false-459184" style="font-weight:bold;" target="_blank" title="Click to know more about FALSE">FALSE</a>.<br/> If Statement - I is false but Statement - II is true</p>Answer :A</body></html>
Discussion
37190.

The radius of gyration of a uniform rod of length L about an axis passing through its centre of mass is

Answer» <html><body><p>`(L)/(<a href="https://interviewquestions.tuteehub.com/tag/sqrt-1223129" style="font-weight:bold;" target="_blank" title="Click to know more about SQRT">SQRT</a>(<a href="https://interviewquestions.tuteehub.com/tag/12-269062" style="font-weight:bold;" target="_blank" title="Click to know more about 12">12</a>))`<br/>`(L^2)/(sqrt(12))`<br/>`(L)/(sqrt3)`<br/>`(L)/(<a href="https://interviewquestions.tuteehub.com/tag/sqrt2-3056932" style="font-weight:bold;" target="_blank" title="Click to know more about SQRT2">SQRT2</a>)`</p>Solution :`I = Mk^(2) = (ML^(2))/(12) <a href="https://interviewquestions.tuteehub.com/tag/therefore-706901" style="font-weight:bold;" target="_blank" title="Click to know more about THEREFORE">THEREFORE</a> <a href="https://interviewquestions.tuteehub.com/tag/k-527196" style="font-weight:bold;" target="_blank" title="Click to know more about K">K</a> = (L)/(sqrt(12))`</body></html>
Discussion
37191.

Two wheels of M.I. 3kg m^(2) and 5 kg m^(2) are rotating at a rate of 600 rpm and 800 rpm respectively in opposite directions. If are coupled so as to rotate with the same axis of rotation, the resultent speed of rotation (in rpm)

Answer» <html><body><p>275<br/>350<br/>210<br/>420</p>Answer :A</body></html>
Discussion
37192.

When a load of 20 kg is hung from a wire of cross sectional area 1mm^2, its elongated length is 600.5 cm. IF the load is withdrawn the wire shrinks by 0.5 cm in length. Calculate the young's modulus for the material of the wire.

Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :`2.35 <a href="https://interviewquestions.tuteehub.com/tag/times-1420471" style="font-weight:bold;" target="_blank" title="Click to know more about TIMES">TIMES</a> 10^12 <a href="https://interviewquestions.tuteehub.com/tag/dyn-2596635" style="font-weight:bold;" target="_blank" title="Click to know more about DYN">DYN</a> .cm^-2`</body></html>
Discussion
37193.

The volume (V) of a moatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is

Answer» <html><body><p>`(2)/(5)`<br/>`(2)/(3)`<br/>`(1)/(3)`<br/>`(2)/(7)`</p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/given-473447" style="font-weight:bold;" target="_blank" title="Click to know more about GIVEN">GIVEN</a> process is isobaric. <br/> `:. dQ = nC_(P)dT`, where `C_(P)` is <a href="https://interviewquestions.tuteehub.com/tag/specific-1220917" style="font-weight:bold;" target="_blank" title="Click to know more about SPECIFIC">SPECIFIC</a> heat at constant pressure. <br/> or `dQ = n((5)/(2)R)dT` Also, `<a href="https://interviewquestions.tuteehub.com/tag/dw-943287" style="font-weight:bold;" target="_blank" title="Click to know more about DW">DW</a> = PdV = nRdT (because PV = <a href="https://interviewquestions.tuteehub.com/tag/nrt-1109890" style="font-weight:bold;" target="_blank" title="Click to know more about NRT">NRT</a>)` <br/> Required <a href="https://interviewquestions.tuteehub.com/tag/ratio-13379" style="font-weight:bold;" target="_blank" title="Click to know more about RATIO">RATIO</a> = `(dW)/(dQ) = ((nRdT)/(n(5)/(2)R)dT) = (2)/(5)`</body></html>
Discussion
37194.

A block of mass M is hanging over a smooth and light pulley through a light string. The other end of the strinig is pulled by a constant force F. The kinetic energy of the block increases by 20J n 1s.

Answer» <html><body><p>the <a href="https://interviewquestions.tuteehub.com/tag/tension-1241727" style="font-weight:bold;" target="_blank" title="Click to know more about TENSION">TENSION</a> in the string is Mg<br/>The tension is the string is F<br/>The work <a href="https://interviewquestions.tuteehub.com/tag/done-2591742" style="font-weight:bold;" target="_blank" title="Click to know more about DONE">DONE</a> by the tension on the <a href="https://interviewquestions.tuteehub.com/tag/block-18865" style="font-weight:bold;" target="_blank" title="Click to know more about BLOCK">BLOCK</a> is 20 <a href="https://interviewquestions.tuteehub.com/tag/j-520843" style="font-weight:bold;" target="_blank" title="Click to know more about J">J</a> in the above 1s.<br/>the work done by the <a href="https://interviewquestions.tuteehub.com/tag/force-22342" style="font-weight:bold;" target="_blank" title="Click to know more about FORCE">FORCE</a> of gravity is -20J in the above 1s.</p>Answer :B</body></html>
Discussion
37195.

A diatomic ideal gas is used in a carnot engine as the working substance. If during the adiabatic expansion part of the cycle, the volume of the gas increases from V to 32 V, the efficiency of the engine is ……………… .

Answer» <html><body><p>0.25<br/>0.5<br/>0.75<br/>0.99</p>Solution :`<a href="https://interviewquestions.tuteehub.com/tag/tv-662255" style="font-weight:bold;" target="_blank" title="Click to know more about TV">TV</a>^(gamma-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)="constant"` <br/> `<a href="https://interviewquestions.tuteehub.com/tag/rarr-1175461" style="font-weight:bold;" target="_blank" title="Click to know more about RARR">RARR</a>""(T_(2))/(T_(1))=((V_(1))/(V_(2)))^(gamma-1)=((1)/(32))^((7)/(5)-1)` <br/> `(T_(2))/(T_(1))=((1)/(2^(5)))^((2)/(5))=(1)/(4)` <br/> `"<a href="https://interviewquestions.tuteehub.com/tag/efficiency-20674" style="font-weight:bold;" target="_blank" title="Click to know more about EFFICIENCY">EFFICIENCY</a>"eta=1-(T_(2))/(T_(1))=1-(1)/(4)=0.75`</body></html>
Discussion
37196.

Four solids are shown in cross section. The sections have equal heights and equal maximum widths. They have the same mass. The one which has the largest rotational inertia about a perpendicular through the centre of mass is

Answer» <html><body><p><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/MMC_PHY_C07_E01_070_O01.png" width="30%"/> <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/MMC_PHY_C07_E01_070_O02.png" width="30%"/> <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/MMC_PHY_C07_E01_070_O03.png" width="30%"/> <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/MMC_PHY_C07_E01_070_O04.png" width="30%"/> </p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :A</body></html>
Discussion
37197.

Below are four equations expressing relationships between qualities. 'g' gravitational field strengths, r radius , rho a density, G the universal constant of gravitational, m a mass and T a time period. Which of the equations are true. (a) g T^(2) = 4pi r^(2)(b) (4)/(3) pi rho G r^(2) = g (c) g r^(2) = Gm(d) g = (4)/(3) pi rho Gr

Answer» <html><body><p>only a &amp; <a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a> are <a href="https://interviewquestions.tuteehub.com/tag/true-713260" style="font-weight:bold;" target="_blank" title="Click to know more about TRUE">TRUE</a> <br/>only b &amp; <a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a> are true <br/>only c &amp; d are true <br/>only a, b &amp; c are true </p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :C</body></html>
Discussion
37198.

Find ratio of radius of gyration of a disk and ring of same radii at their tangential axis in plane

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :For <a href="https://interviewquestions.tuteehub.com/tag/disc-955290" style="font-weight:bold;" target="_blank" title="Click to know more about DISC">DISC</a> `MK^(2) = (5//4)MR^(2)`, For <a href="https://interviewquestions.tuteehub.com/tag/ring-1189545" style="font-weight:bold;" target="_blank" title="Click to know more about RING">RING</a> `MK^(2) = (3//2)MR^(2)`, <a href="https://interviewquestions.tuteehub.com/tag/ratio-13379" style="font-weight:bold;" target="_blank" title="Click to know more about RATIO">RATIO</a> = `sqrt(5)//sqrt(<a href="https://interviewquestions.tuteehub.com/tag/6-327005" style="font-weight:bold;" target="_blank" title="Click to know more about 6">6</a>)`</body></html>
Discussion
37199.

A body of mass 15kg is raised from certain depth. If the work done in raising it by 10m is 1620J, its velocity at this position is (g= 10 ms^(-2))

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a> ms^(-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a> ms^(-1)`<br/>`1 ms^(-1)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a> ms^(-1)`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :B</body></html>
Discussion
37200.

Three particles of identical masses .m. are kept at the vertices of an equilateral triangle of each side length.a.. Find the gravitational force of attraction on any one of the particles.

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> : Let `F_A` and `F_B` be the forces due to the <a href="https://interviewquestions.tuteehub.com/tag/masses-1088822" style="font-weight:bold;" target="_blank" title="Click to know more about MASSES">MASSES</a> at A and B on the mass at <a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a>. <br/>Here `F_A=F_B` <br/>Hence the Resultant <a href="https://interviewquestions.tuteehub.com/tag/force-22342" style="font-weight:bold;" target="_blank" title="Click to know more about FORCE">FORCE</a> on the mass at C <br/> `F=2F_A cos theta//<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a> =2. (Gm^2)/a^2 cos 30^@` <br/> `=2xx(Gm^2)/a^2xxsqrt3/2 = sqrt3(Gm^2)/a^2` <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_NEO_CAO_PHY_XI_V01_B_C09_SLV_011_S01.png" width="80%"/></body></html>
Discussion