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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The pressure of a gas at 100^(@)C is 2 atm. When the gas is heated by keeping volume constant, at what temperature the pressure raises to 3 atm ? |
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Answer» |
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| 2. |
A mass m, which is attached to a spring with spring constant k, oscillates on a horizontal table, with amplitude A. At an instant when the spring is streched by sqrt(3) A//2, a second mass m is dropped vertically onto the original mass and immediately sticks to it. what is the amplitude of the resulting motion- |
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Answer» `SQRT((3)/(2))A` |
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| 3. |
A particle projected at angle 60^(@)with speed 10sqrt(3),from the point 'A' as shown in the figure. At the same time the wedge is made to move with speed10sqrt(3) towards right as shown in the figure. |
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Answer» time taken by PARTICLE to strike WEDGE is 2 sec |
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| 4. |
A merry-go-round, made of ring-like platform of radius R and mass M is revolving with angular speed omega. A person of mass M is standing on it. At one instant, the person jumps off the round, radially away from the centre of the round (as seen from the round). The speed of the round of afterward is ............ |
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Answer» `2omega` `omega_(1)=omega` `I_(2)=MR^(2)+0=MR^(2)` (after) Now, `I_(1)omega_(1)=I_(2)omega_(2)` `THEREFORE omega_(2)=(I_(1)omega_(1))/(I_(2))` `therefore omega_(2)=2omega` |
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| 5. |
Give the formula for the moment of couple. |
| Answer» SOLUTION :Moment of COUPLE = (MAGNITUDE of any one of the two forces) `xx` PERPENDICULAR DISTANCE between the two forces. | |
| 7. |
What are stationary waves? write down the characteristics of stationary waves. |
| Answer» Solution :When two IDENTICAL waves of same amplitude and frequency travelling in OPPOSITE directionals with same speed along the same path superpose each other , the RESULTANT wave does not travel in the EITHER direction and is called stationary or standing waves . | |
| 8. |
When 0.15 kg of ice of 0" "^(@)C mixed with 0.30 kg of water at 50" "^(@)C in a container, the resulting temperature is 7.6" "^(@)C. Calculate the heat of fusion of ice. ""(S_("water")=4186" J kg"^(-1)K^(-1)) |
| Answer» SOLUTION :`L_(F)=3.23xx10^(5)" JKG"^(-1)` | |
| 10. |
Two capillary tubes of same length but different radii r_(1)andr_(2) are fitted in parallel to the bottom of a vessel. The pressure head is P. What should be the radius of a single tube that can replace the two tubes so that the rate of flow is same as before |
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Answer» `r_(1)^(4)+r_(2)^(4)` |
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| 11. |
A spring of force constant k is cut info two pieces such that one piece is double the length of the other. Then, the long plece will have a force constant of |
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| 12. |
(A): Water at the foot of the water fall is always at different temperature from that at the top. (R ): The potential energy of water at the top is converted into heat energy during falling. |
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Answer» Both 'A' and 'R' are TRUE and 'R' is the correct EXPLANATION of 'A's |
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| 13. |
A boy of mass M is applying a horizontal force to slide a box of mass M_(1) on rough horizontal surface. The coefficient of friction between the shoe of the boy and the floor is mu and that between the box and the floor is ‘mu_(1)’ In which of the following cases is it certainly not possible to slide the box ? |
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Answer» `multmu_(1), M ltM_(1)` |
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| 14. |
Unit used to measure nuclear diameters is |
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Answer» fermi |
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| 15. |
A simple pendulum of length l and mass m free to oscillate in vertical plane. A nail is located at a distance d=l-a vertically below the point of suspension of a simple pendulum. The pendulum bob is released from the position where the string makes an angle of 90^@ from vertical. Discuss the motion of the bob if (a) l=2a and (b) l=2.5a. |
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Answer» Solution :a. `l=2a`, velocity at lowest point from ENERGY conservation `0+mg2a=1/2mv^2` `v=sqrt(4ga)` Here the radius of CIRCLE is a about nail and velocity at lowest point is not sufficient to COMPLETE the loop. Therefore, MOTION of bob is the combination of circular and projectile motion. Because the velocity at lowest point LIES between `sqrt(3ga)` and `sqrt(5ga)`. b. `l=2.5a`, Velocity at lowest point from energy conservation `0+mg(2.5a)=1/2mv^2impliesv=sqrt(5ga)` here radius of circle is a about nail and velocity at lowest point is just sufficient to complete the loop so that here looping the loop about nail. |
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| 16. |
If 27 small spheres each of M.I. T about their diametrical axis are combined to form a big sphere, then the M.I. of the big sphere about its diameter is |
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Answer» 243 I |
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| 17. |
In column - I some physical situations are mentioned, in column - II corresponding variations of resultant quantities percentasge errors are mentioned. Match column - I entries appropriately with column - II entries |
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| 18. |
A load of mass m falls from a height h on to the scale pan hung from a spring as shown in the adjoining figure. If the spring constant is k and mass of the scale pan is zero and the mass m does not bounce relative to the pan, then the amplitude of vibration is |
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Answer» `(mg)/(k)` `mgh=(1)/(2)kx_(0)^(2)-mgx_(0)` where, `x_(0)` is maximum elongation in spring (when PARTICLE is in its LOWEST EXTREME position). or `(1)/(2)kx_(0)^(2)-mgx_(0)-mgh=0` or `x_(0)^(2)-(2mg)/(k)x_(0)-(2mg)/(k)h=0` `therefore""x_(0)=((2mg)/(k)pmsqrt([((2mg)/(k))^(2)+4xx(2mg)/(k)h]))/(2)` `because` Amplitude=elongation in spring for lowest extreme position-elongation in spring for equilibrium position `=x_(0)-x_(1)=(mg)/(k)sqrt((1+(2hk)/(mg)))` |
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| 19. |
A car starts from rest, accelerates uniformly for 4 seconds and then moves with uniform velocity . Which of the (x-t) graphs shown in fig. represents the motion of the car upto t=7s ? |
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Answer»
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| 20. |
ML^(2)T^(-2)I^(2) is the dimensional formula for |
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Answer» SELF INDUCTANCE |
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| 21. |
(A) Although the surfaces of a google lens are curved, it does not have any power. ( R) In case of goggles, both the curved surfaces have equal radii of curvature. |
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Answer» Both A and R are true and R is the CORRECT EXPLANATION of A |
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| 22. |
A person of mass 60 kg is in a lift. The change in the apparent weight of the person, when the lift moves up with an acceleration of 2ms^(-2) and then down with an acceleration of 2ms^(-2) is ("take g = "10 m//sec^(2)) |
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Answer» 120 N |
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| 23. |
The blades of a windmill sweep out a circle of area A. Assume that the windmill converts 25% of the wind's energy into electrical energy, and that A= 30 m^(2), v= 36 km/h and the density of air is 1.2 kgm^(-3). What is the electrical power produced? |
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Answer» <P> SOLUTION :`P= 4.5 KW` |
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| 24. |
A trolley of mass 360 kg is lying on a horizontal frictionless surface. A mas of mass 40 kg runs with uniform speed on the trolley by a distance of 2m in 0.5 second. What is the velocity of the trolley relative to earth ? |
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Answer» 0.8 m/s |
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| 25. |
Calculate the minimum work that must be done to compress 1.0 gm of hydrogen at N.T.P. to half its initial volume. Given R =8.314 J mol ^(-1) K ^(-1). |
| Answer» Solution :`W = 2.303 xx r T LOG _(10 ) V _(2) //V _(1) = 2. 303 xx 14. 157 xx 273 log _(10) (0.5) =- 786. 55 J` | |
| 26. |
For what value of 'h' of orifice below the jet the range will be maximum ? |
| Answer» SOLUTION :For a maximum RANGE `(DX)/(DH)=(H-2h)=0""THEREFORE h=H/2` | |
| 27. |
C_(p)is always greater than C_(v)for a gas. Whichof the following statements provide, partly or wholly, the reason for this? a) No work is done by a gas at constant volume b) When a gas absorbs heat at constantpressure, its volume must change c) For the same change in temperature, theinteral energy of a gas changes by a smallar amount at constant volume than at constantpressure d) The internal energy of an ideal gas is afunction only of its temperature |
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Answer» only a,B are CORRECT |
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| 28. |
A brass disc is stuck in a hole of a steel plate. Should you heat the system to free the disc from the hole? Given, alpha for brass =19 times 10^(-6@)C^(-1)" and " alpha for steel =12 times 10^(-6@)C^(-1). |
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Answer» Solution :To free the disc from the hole, the system should cooled. Since `alpha_(brass) GT alpha_(steel)`, and INITIALLY the radii of the disc and the hole were the same, the disc EXPANDS more on HEATING and GETS stuck more tightly. On cooling, the disc contracts more than the hole, and thus becomes free. |
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| 29. |
Number of significant digits in 3256........... |
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Answer» 1 |
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| 30. |
An iron cube , of edge10 cm ,painted black is at a temperatureof 127^(@) C keptin aroom of tempeature27^(@)C. Ifthe densityand specific heat capacityof ironbe 7600 kg//m^(2)and 470 J// Kg - K , findthe initial rate of coolingof the cube. |
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Answer» Solution :Here , area `A = 6a^(2) ` and volume`V = a^(3) , a= 10 xx 10^(2)m ,e= 1 ` ( `because` the surfaceis painted black ). `rho = 7600 kg // m^(3) , s = 470 J.Kg - K, T = 400 K and T_(0) = 300K`the rate of cooling of a hot bodyis given by` - (dT)/(dt) = (Ae sigma)/(rho Vs)(T^(4) - T_(0)^(4))= (6a^(2) sigma)/( rhoa^(3)s) (T^(4) - T_(0)^(4))` `= (6 xx 5.67 xx 10^(-8) W (400^(4) - 300^(4))K^(4))/((7600(kg)/(m^(3)))((470J)/(Kg - K))m^(2) - K^(4) (10 xx 10^(-2) m))=16.67 xx 10^(-3) K//s` |
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| 31. |
Number of significant digits in 0.030400............. |
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Answer» 6 |
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| 32. |
A particle stars from origin at t=0 with a velocity 5.0hatim//s and moves in x-y plane under action of a force which produces a constant acceleration of (3.0hati+2.0hatj) m//s^(2). (a)What is the y- coordinate of the particle at the instant its x - coordinate is 84 m ? (b) What is the speed of the particle at this time ? |
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Answer» Solution :From Eq . (4.34a) for `r_(0)=0`, the POSITION of the PARTICLE is given by `r(t)=v_(0)t+(1)/(2)at^(2)` `=5.0hati+(1//2)(3.0hati+2.0hatj)t^(2)` Therefore , `x(t)=5.0t+1.5t^(2)` `y(t)=+1.0t^(2)` Given`x(t)=84m.t=`? `5.0t+1.5t^(2)=84rArrt=6s` At`t=6s,y=1.0(6)^(2)=36.0m` Now , the velocity `v=(dr)/(dt)=(5.0+3.0)hati+2.0hatj` At `t=6s,v=23.0hati+12.0hatj` speed `=|v|=sqrt(23^(2)+12^(2))~=26 "m s"^(-1)`. |
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| 33. |
We plot the graph having temperature in""^(@)C on x - axis and in ""^(@)F on y - axis. If the graph is straight line, then the correct statement is |
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Answer» the line INTERCEPTS the positive X - axis |
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| 34. |
A particle executing SHM crossed points A and B with the same velocity. Having taken 3 s in passing from A to B, it returns to B after another 3s. The time period is: |
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Answer» 15s ` = 2 xx (3 + 3) , T = 12 s ` |
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| 35. |
Two particles P and Q of mass 1 kg and 3 kg respectively start moving towards each other form rest under mutual attraction. What is the velocity of their center of mass ? |
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Answer» SOLUTION :MASS of first particle P is `m_(1)=1kg` Mass of second particle Q is `m_(2)=3kg` Velocity of particle P `=` Velocity of particle Q but in OPPOSITE Q but in opposite direction `:.` Velocity of centre of mass `v_(cm)=(m_(1)v_(1)+m_(2)v_(2))/(m_(1)+m_(2))` `=0` |
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| 36. |
In a double star system two stars of masses m_(1) and m_(2) separated by a distance 'd' rotates about their centre of mass. Then the common angular velocity and time period is |
Answer» SOLUTION : The gravitational force between the masses provides the necessary centripetal force `(Gm_(1)m_(2))/(d) = m_(1)r_(1) omega^(2) RARR (1)` The DISTANCE of centre of mass from `m_(1)` is `r_(1) = (m_(2)d)/(m_(1)+m_(2))rarr (2)`, From (1) and (2) `(Gm_(1)m_(2))/(d^(2)) = (m_(1)m_(2)d)/(m_(1)+m_(2)).omega^(2)` (or) `omega^(2) = (G(m_(1)+m_(2)))/(d^(3))` (or) `omega = sqrt((G(m_(1) + m_(2)))/(d^(3)))` |
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| 37. |
A large bottle open at top is fitted with a siphon made of capillary glass tubing at its bottom. Find the ratio of the times taken to empty the bottle when it is filled (1) with water (ii) with petrol of density 0.8 cgs unit. The viscosity of water and petrol are 0.01 and 0.02 cgs units respectively |
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Answer» `1:2` |
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| 38. |
A gaseous mixture consists of 16 g of helium and 16 g of oxygen. The ratio of C_(P) and C_(V) is |
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Answer» 1.4 |
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| 39. |
When there is no external force, the shape of a liquid drop is determined by |
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Answer» Surface TENSION of the LIQUID |
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| 40. |
Weight is suspended to the end of elastic spring its increaed length depends upon what ? |
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Answer» Solution :(1 ) `Delta l prop MG ` (weight)(2) `Delta l prop l` (Original length) (3)` Delta l prop (1)/(A)` (Cross SECTION of WIRE) (4) Type of SPRING `to` on spring CONSTNAT |
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| 41. |
At the maximum height of a body thrown vertically up |
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Answer» VELOCITY is not ZERO but ieceleraton is zero |
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| 42. |
A sphere is rotating about a siameter |
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Answer» The particles on the SURFACE of the SPHERE do not have any linear acceleration |
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| 43. |
Water rises in a capilaary tube to a height of 2.0cm. In another capilary tube of radius one third of the first, water remains at a partricular height inside it. Find the height of water in the second capillary. |
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Answer» SOLUTION :Given `h_(1)=2cm""r_(2)=(r_(1)/3)` since `h ALPHA 1/R ""h_(2)/h_(1)=r_(1)/r_(2)` i.e,` h_(2)=(r_(1)/r_(2))h_(1)=((3r_(2))/(r_(2))h_(1)=3 XX 2,""i.e, h_(2)=6cm.` |
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| 44. |
Estimate the average thermal energy of a helium atom at (i) room temperature (27 ^(@)C). (ii) the temperature on the surface of the Sun (6000 K), (iii) the temperature of 10 million kelvin (the typical core temperature in the case of a star). |
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Answer» `1.7 xx 10^(-16)J` |
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| 45. |
A body is moving under the expense of a constant power. If .X. is the displacement in time .t., then .x. is proportional to |
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Answer» `t^(2//3)` |
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| 46. |
Five moles of hydrogen when heated through 20 K expand by an amount of 8.3xx10^(-3)m^(3)under a constant pressure of10^(5)N//m^(2). " If "C_(v)=20J//"mole"K,"Find"C_(p). |
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Answer» 28.3 |
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| 47. |
Four spheres, a, b, c, d of same material and equal volume are dropped into four liquids of densities d_(1),d_(2),d_(3) and d_(4)(d_(1)gtd_(2)gtd_(3)gtd_(4)). The ascending order of the terminal velocities (eta is same) |
| Answer» Answer :A | |
| 48. |
A particle of mass m moves on a circularpath ofradius r . Its centripetal acceleration is kt^(2), where k isa constant andt is time . Express power as function of t . |
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Answer» <P>kmt ` = kt^(2) ` is given Now , TAKING derivation w.r.ttime , t . `(2V (dv)/(dt)) 1/r = 2 kt` Multiplyingon both sides by .m. ` :.MV (dv)/(dt) = mktr` ` :. FV = ktmr"" ( :. F = ma = m (dv)/(dt))` ` :. P = ktmr"" (:. P = Fv)` |
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| 49. |
If four forces act at a point .O. as shown in the figure and if O is in equalibrium then the value of .theta. & .P. are |
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Answer» `15^(0), 10sqrt(2)N` |
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| 50. |
{:(,"Measured value",,"Significant figures"),((A),0.0235,(P),5),((B),235xx10^(2),(Q),4),((C ),46.64 div 2.3,(R ),3),((D),234.0,(S),2):} |
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Answer» |
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