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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 14751. |
An artificial satellite is moving in a circular orbit around the earth with a speed equal tohalf the magnitude of escape velocity from the earth.(a)Determine the heightof the satellite above the earth.s surface. (b) if the satellite is stopped suddenly in its orbit and allowed to fall freely onto the earth, find the speed with which it hits the surface of the earth.[g=9.8 m s^(-2) and R_E=6400 km] |
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Answer» Solution :(a) We KNOW that for SATELLITE motion `v_0=SQRT((GM)/r) =R sqrt(G/(R+h))` [as `g=(GM)/R^2` and r=R+h] In this problem `v_0=1/2v_e=1/2 sqrt(2gR)` [as `v_e=sqrt(2gR)` ] So `(R^2g)/(R+h)=1/2gR`, i.e., 2R=h+R or h=R=6400 km (b) By conservation of ME `0+[-(GMm)/r]=1/2mv^2+[-(GMm)/R]` or `v^2=2GM[1/R-1/(2R)]` [as r=R+h =R+R=2R] `v=sqrt((GM)/R)=sqrt(gR)=sqrt(10xx6.4xx10^6)`= 8 km/s |
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| 14752. |
How does the time period of a simple pendulum depend on the acceleration due to gravity at the given place? |
| Answer» Solution :The time PERIOD of SIMPLE PENDULUM is INVERSELY proportional to the square ROOT of the acceleration due to gravity. | |
| 14753. |
Resultant of two vectors which are parallel to each other and are in the same direction is obtained by . . . . Of vectors . |
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Answer» addition |
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| 14754. |
What is system of particle? |
| Answer» Solution :Set of more than ONE particles mutually INTERSECT each other is known as SYSTEM of PARTICLE. | |
| 14755. |
Derive the expressions for displacement velocity and acceleration of a particle executes S.H.M. |
Answer» SOLUTION :Displacement, velocity and ACCELERATION at DIFFERENT INSTANT of time. 
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| 14756. |
An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters 2.5 cm and 3.75 cm. The ratio of the velocities in the two pipes is |
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Answer» `9:4` `a_(1)v_(1)=a_(2)v_(2)` or `(v_(1))/(v_(2))=(a_(2))/(a_(1))=(pid_(2)^(2)//4)/(pid_(1)^(2)//4)=((d_(2))/(d_(1)))^(2)=((13.75)/(2.5))^(2)=(9)/(4)` |
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| 14757. |
In case of a simple harmonic motion, which of the following statements is not true? |
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Answer» the moving particle repeats the same path periodically |
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| 14758. |
Arrange the following glass convexlenses in increasing order of their focal power. a) R_1=12cm R_2=6cm b) R_1=10cm R_2=5cm c) R_1=15cm R_2=5cm d) R_1=15cm R_2=10cm |
| Answer» Answer :C | |
| 14759. |
A copper calorimeter has mass of 180 g and contains 450 g of water and 50 g of ice, all at 0^(@)C. Dry steam is passed into the calorimeter until a certain temperature (theta) is reached. The mass of the calorimeter and its contents at the end of the experiment increased by 25 g. Assume no heat loss to the surrounding and take specific heat capacities of water and copper to be 4200 J kg^(-1) K^(-1) and 390 J kg^(-1) K^(-1), respectively. Take specific latent heat of vaporization of water to be 3.36 xx 10^(5) J kg^(-1) and 2.26 xx 10^(6) J kg^(-1) respectively. (a) Find the final temperature theta (b) If steam enters into the system at a steady rate of 5 g min^(-1), plot the variation of temperature of the system till final temperature theta is attained. |
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Answer» (B) `(##IJA_PHY_V02_C02_E01_027_A01##)` |
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| 14760. |
Along the direction of propagation of wave, distance between two particles, having same phaes is called wavelength of wave. |
| Answer» SOLUTION :FALSE. Because this phase difference should be `2PI` rad. | |
| 14761. |
A boy walks to his school at adistance of 6km withconstant speed of 2.5 kmph and walks back with a constant speed of 4 kmph. His average speed for round trip expressed in kmph is |
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Answer» `24//13` |
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| 14762. |
A body is projected with a velocity 60ms^(-1) at 30^(@) to horizontal. Its initial velocity vector is |
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Answer» `10 hat(i) + 10 sqrt(3) hat(J)` |
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| 14763. |
A force vec(F) = 5hat(i) - 3hat(j) + 2hat(k) moves a particle from vec(r_(1))=2hat(i)+7hat(i)+4hat(k)" ""to" " " vec(r_(2))=5hat(i)+2hat(j)+8hat(k). Calculate the workdone. |
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Answer» 38 units |
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| 14764. |
What should be the displacement of a particle, executing SHM, from its position of equilibrium so that its acceleration is half of its maximum acceleration? |
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Answer» SOLUTION :According to the definition of SHM, acceleration `prop` displacement. So, acceleration of the PARTICLE will be half of its MAXIMUM value, if the displacement is half of the maximum displacement, i.e., half the AMPLITUDE. |
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| 14765. |
The position vector of a moving particle at .t. sec is given by vec(r) = 3hat(i) + 4t^(2)hat(j) - t^(3)hat(k). Its displacement during an interval of t = 1s to 3sec is |
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Answer» `hat(j) - hat(k)` |
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| 14766. |
An object is released from rest. The time it takes to fall through as distance h and the speed of the object as ilt fallls through this distance are measured with a pendulum clock. The entire apparatus is taken on the moon and the experiment is repeated |
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Answer» the MEASURED TIMES are same |
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| 14767. |
A particle on the tough of a wave art any instant will come to the mean position after a time (7= time period) |
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Answer» `T/2` |
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| 14768. |
Even after breakup of one prong of tunning fork it produces a round of same frequency, then what is the use of having a tunning fork with two prongs ? |
| Answer» SOLUTION :TWO prongs of a tunning fork set each other in RESONANT vitorations and help to maintain the VIBRATIONS for a longer TIME. | |
| 14769. |
Gravitational acceleration is …... proportional to the distance from centre inside the surface of earth. |
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Answer» |
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| 14770. |
A sphere cannot roll on a smooth inclined surface. The motion of a rigid body which is pivoted or fixed in some way is rotation. |
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Answer» If both assertion and reason are true and reason is the correct explanation of assertion. |
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| 14771. |
What are the unit vectors along the negative x-direction, negative y-direction, and negative z-direction? |
Answer» Solution :The unit vectors along the negative DIRECTIONS can be shown as in the following figure.  Then we have: The unit vector along the negative X DIRECTION `-=hati` The unit vector along the negative y direction `=-HATJ` The unit vector along the negative z direction `=-HATK` |
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| 14772. |
A body attached to a spring is executing SHM. If the force constant of the spring is increased then what will be the change in the frequency of oscillation? |
| Answer» SOLUTION :FREQUENCY will INCREASE | |
| 14773. |
"The value of the escape velocity v_efor a stationary body on the surface of a planet is directly proportional to the mass and the radius of the planet”. Is this statement true? If not, correct it and write it. |
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Answer» Solution :`implies`This statement is false. Correct statement : "The value of the escape VELOCITY `v_e`for a stationary body on the surface of a planet is directly proportional to the SQUARE ROOT of the RATIO of mass to radius of planet". |
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| 14774. |
Four mass capilary tubes a,b,c and d having diameter, 2mm, 1 mm, 0.8 mm and 0.6 mm are dipped in four beakers containing water with a tube vertically b tube 30^(@)c tube 45^(@) and d tube 60^(@) inclination with the vertical arrange the lengths of water column in the tubes in descending order |
| Answer» Answer :A | |
| 14775. |
Define kinematic viscosity. |
| Answer» Solution :The ratio of coefficient of VISCOSITY `eta` and the DENSITY `RHO` of a LIQUID is called kinematic viscosity. | |
| 14776. |
(Assertion) :A body may be accelerated even when it is moving at uniform speed. (Reason) : When direction of motion of the body is changing then body may have acceleration. |
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Answer» Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A) |
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| 14777. |
Solve the following and express the result to an appropriate number of significant figures. (v) (2.51xx10^(-4)xx1.81xx10^(7))/(0.4463) |
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Answer» SOLUTION :`(2.51xx10^(-4)xx1.81xx10^(7))/(0.4463)=10.1795xx10^(3)` `=10.2xx10^(3)` (Rounded off to there SIGNIFICANT figres) |
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| 14778. |
Suppose the exact charge neutrality does not in a world and the electron has a charge 1% less in magnitude than the proton. Calculate the Coulomb force acting between two blocks of iron eachof mass 1 kg separated by a distante of 1m. Number of protons in an iron atom =26 and 58 kg of iron contains 6xx10^28 atoms. |
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Answer» Solution :Each atom of iron will have a NET positive charge `26xx0.01xx1.6xx10^-19`C on it in the assumed WORLD. The total positive charge on a 1 KG block would be (6xx10^26)/58xx26xx1.6xx10^(-10)C` `=4.3 XX10^5c` The Coulomb force between the two blocks is `=1/(4piepsilon_0) (q_1 q_2)/r^2= (9.0xx10^9 N-m^2/C^2xx(4.3xx10^5C)^2)/(1 m)^2) `=1.7xx10^21N`. A tremendous force indeed! |
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| 14779. |
An ideal gas has an adiabatic coefficient gamma . In some process, the molar heat capacityvaries as C= alpha //T, where alphais a constant. Find (a) the work performed by one mole of gas during its heating from the temperature T_0 to the temperature etatimes higher, and (b) the equation of the process in the variable P, V. |
| Answer» Solution :`PV^( GAMMA) .e^((alpha ( gamma -1))/(PV))`= CONSTANT | |
| 14780. |
A particle exccutes SHM of amplitude A. At what distance from the mean position id its kinetic energy equal to its potential energy? |
| Answer» SOLUTION :`1/2momega^2(A^2-Y^2)=1/2momega^2y^2` , then y=`A/sqrt2` | |
| 14781. |
A car starts to move from rest with uniform acceleration 10 ms^(-2)then after 5 sec, what is its velocity? |
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Answer» SOLUTION :`a = 10 ms^(-2) : t = 2s : U = 0 : v = ?` `v = u + at` ` v = 0 + 10 xx 2` ` = 20 ms^(-1)` |
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| 14782. |
Which law of Newton defines an ‘inertial frame of reference’ ? |
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Answer» FIRST LAW of motion |
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| 14783. |
A particle of mass m moving with velocity u collides elastically with a particle of mass 3m at rest. After collision the heavier particle moves with velocity. |
| Answer» Answer :C | |
| 14784. |
When beats are formed by two waves of frequencies n_(1) and n_(2) the amplitude varies with frequency equal to |
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Answer» `n_(1)-n_(2)` |
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| 14785. |
(A) : At the centre of earth, a body has centre of mass but no centre of gravity. (R ) : Acceleration due to gravity is zero at the centre of earth. |
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Answer» Both 'A' and 'R' and true and 'R' is the CORRECT EXPLANTATION of 'A' |
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| 14786. |
ifmoon move in an elliptical orbit around the earth. The mass of the moon is very small compared to the mass of the earth because |
| Answer» Solution :The ACCELERATION of S is ALWAYS directed TOWARDS the CENTRE of the EARTH. | |
| 14787. |
A ball starts falling with zero initial velocity on a smooth inclined plane forming an angle alpha with the horizontal. Having fallen the distnace h, the ball rebounds elastically off the inclined plane. At what distance from the impact point will the ball rebound for the second time? |
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Answer» Solution :The SITUATION is shown in fig Let the ball rebound from point A and return to the plane at point B, MOVING along the trajectory shown in diagram.  Let `AB=l` Velocity of rebound at point `A,V=sqrt(2gh)` Velocity COMPONENT perpendicular to plane `=v cos alpha` velocity component along the plane `=v sin alpha` Retardation perpendicular to plane `=g cos alpha` Acceleration along the plane `=g sin alpha` If the ball comes to REST at this highest point after time, t then `(v cos alpha-g cos alpha.t)=0` or `t=v/g` Time of fight of the ball `T=2t=(2v)/g` Range of the ball along the plane `l=(vsin alpha)T+1/2(g sin alpha)T^(2)` `=v sin alpha.(2v)/g+1/2. g sin alpha(4v^(2))/(g^(2))` `=(2v^(2))/g sin alpha+(2v^(2))/g sin alpha` `=4(v^(2))/g sin alpha=4((2gh))/gsin alpha` `( :. v=sqrt(2gh))"":. l=8h sin alpha` |
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| 14788. |
A column of Hg of 10 cm length is contained in the middle of a narrow horizontal 1 m long tube which is closed at both ends. Both the halves of the tube conl.ain air at a pressure 76 cm of Hg. By what distance will the column of Hg be displaced, if the tube is held vertical? (Assume temperature to be constant) |
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Answer» Solution :If initially the LENGTH of air column on each side is L, according to the GIVEN problem, 2L + 10 = 100 , i.e., L = 45 cm ........ (1) Now if the tube is held vertical, the Hg column will be displaced downward by y such that `P_(B)+ 10 = P_(A)`...... (2) Now applying Boyle.s law to air enclosed in side A, `P_(0)LA = P_(A) (L - y) A , " i.e., " P_(A) = (LP_(0))/((L - y)) `....... (3) while for air enclosed in side B, `P_(0) L A = P_(B) (L + y) A ,` i.e, `P_(B) = (LP_(0))/((L + y)) `....... (4)  Substituting the values of `P_(A) and P_(B) ` from euqation (3) and (4) in (2), with L = 45 and `P_(0)` = 76 cm of Hg, we get `(45 xx 76)/((45 - y)) - (45 xx 76)/((45 + y)) = 10 , " or " y^(2) + 684y- (45)^(2)` = 0 or= y `[ - 684 PM sqrt((684)^(2) + 4 (45)^(2) ) ] `/2 or y = - 342 + 345= 3 cm |
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| 14789. |
(A) Endoscopy involves use of optical fibres to study internal organs ( R) Optical fibres work based on phenomenon of total internal reflection. |
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Answer» Both A and R are TRUE and R is the correct explanation of A |
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| 14790. |
Choose the correct alternative : (a) If the zero of potential energy is at infinityn the total energy of an orbiting satellite is negative of its kinetic/potential energy. (b) The energy required to launch an orbiting satellite out of earth's gravitational influence is more/less than the energy required to project a stationary object at the same height (as the satellite) out of earth's influence. |
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Answer» Solution :`implies` (a) The total ENERGY of an orbiting satellite is negative of its kinetic energy. (b) The energy required to LAUNCH an orbiting satellite out of earth.s gravitational influence is LESS than the energy required to project a STATIONARY object at the same height out of earth.s influence. |
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| 14791. |
Two equal lumps of putty are suspended side by side from two long strings so that they are just touching. One is drawn aside so that its centre of gravity rises a vertical distance h. It is released and then collides inelastically with the other one. The vertical distance risen by the centre of gravity of the combination is - |
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Answer» H. |
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| 14792. |
There is a limit beyond which further polishing of a surface increases rather than decreases frictional force. Explain. |
| Answer» Solution :When the SURFACE is POLISHED beyond certain limit the actual area of contact increases. This increases the force of attraction between the molecules and HENCE friction ALSO increases. | |
| 14793. |
For one complete revolution, the angle sweptby the radius vector is : |
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Answer» `360^(@)` `:. theta = 2 pi` |
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| 14794. |
List few applications of surface tension. |
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Answer» Solution :Applications are:(i) Mosquitoes lay their eggs on the surface of water. To REDUCE the surface tension of water, a SMALL amount of oil is poured. This breaks the elastic film of water surface and eggs are killed by drowing. (ii) Chemical engineers must finely adjust the surface tension of the liquid, so it forms droplets of designed size and so it adheres to the surface without smearing. This is used in desktop printing, to paint automobiles and decorative items. (iii) Specks of dirt get removed when detergents are added to hot WATE while wasing clothes because tension is reduced. (iv) A FABRIC can be made waterproof, by adding suitable waterproof materia (wax) to the fabric. This increases the ANGLE of contact. |
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| 14795. |
Figure shows the orientation of two vectors u and v in the XY-plane If u = a hat(i) + b hat(j) and v = p hat(i) + q hat(j) Which of the following is correct ? |
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Answer» a and p are positive while b and Q are negative |
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| 14796. |
1 unit = …… electric energy . |
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Answer» 3600 ` = 36 xx10^(5) J ` ` : . 1 Unit = 36,000 J ` |
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| 14797. |
The angular momentum of a system of prticles is convserved when |
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Answer» no EXTERNAL force acts upon the system |
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| 14798. |
A light ray is incident on face AB of a prism ABC as shown in figure. The second prims is ketp in such a manner the emergent ray from prism ABC is falling normally on face A'B' of prism A'B'C'. The net deviation by optical system two prisms is (8k) degree. find the value of k. |
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| 14799. |
A cylindrical drum, open the top, contains 30 liters of water. It drains out through a small opening at the bottom. 10 litres of water comes out in time t_(1), the next 10 litres in further time t_(2) and the last 10 liters in further time t_(3). Then, |
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Answer» `t_(1)=t_(2)=t_(3)` |
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| 14800. |
By newton's first law of motion to keep object in motion by …... Velocity no force is required. |
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Answer» |
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