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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. |
A system consists of two identical particles one particle is at rest and the other particle has an acceleration .a.. The centre of mass of the system has an acceleration of |
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Answer» 2a |
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| 2. |
The two ends of a wire are rigidly fixed . If the temperature is decreased by 10^(@) C , find the tension in the string from the given quantities : cross sectional area of the wire= 0 . 01 cm^(2), coefficient of linear expansion of the material of the wire= 16 xx 10^(6_(@)) C^(-1)and Young's modulus= 20 xx 10^(11) dyn * cm^(-2) .If the frequency of transverse wave produced in the wire is twiece the previous value, what was the initial tension in the wire ? |
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Answer» |
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| 3. |
A particle executes S.H.M with amplitude 'A' Ifthe displacement y=A//2 which of the following will be half of its maximum value |
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Answer» KINETIC energy |
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| 4. |
The focal lengths of the objective and the eye - piece of a compound microscope are 2.0 cm and 3.0 cm respectively. The distance between the objective and the eye - piece is 15.0 cm. The final image formed by the eye - piece is at infinity. The two lenses are thin. The distances in centimeters of the object and image produced by the objective measured from the objective respectively. |
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Answer» 2.4 and 12 |
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| 5. |
A 42kg block of icemoving an rough horizontal surface stops due to friction, after some time. If the initial velocity of the decelerating block is 4m/s, the mass of ice in (kg) that has melted due to heat generated by friction is : (latent heat of ice is 3.36 xx 10^(5) J/kg ) |
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Answer» `10^(-3)` |
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| 6. |
If the immediate insignificant digit to be dropped is 5 then there will be two different cases A) If the preceding digit is even, it is to be unchanged and 5 is dropped. B) If the preceding digit is odd, it is to be raised by 1. |
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Answer» Only A is correct |
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| 7. |
A body of mass 5kg starts from the origin with an initial velocity vecu = 30 hati + 40 hatj ms^(-1). If a constant forcevecF = -(hati + 5hatj)acts on the body, the time in which the y-component of the velocity becomes zero is : |
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Answer» 5s |
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| 8. |
(A) : Buoyant force on 1 kg of iron is lesser than Buoyant force on 1 kg of cotton (R ) : Apparent weight of 1 kg of iron is equal to that of 1 kg of cotton in air. |
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Answer» Both (A) and (R ) are true and (R ) is the CORRECT EXPLANATION of (A) |
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| 9. |
A 50 kg astronaut is floating at rest in space 35 m from her stationary 150,000 kg spaceship. About how long will it take her to float to the ship under the action of the force of gravity? |
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Answer» |
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| 10. |
A train standing at the outer singal of a railway station blows a whistle of frequency 400 Hz in still air. (i) What is frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10 m/s, (b) recedes from the platform with a speed of 10 m/s. (ii) What is the speed of sound in each case if the speed of sound in still air is 340 m/s. |
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Answer» SOLUTION :(i) Here, n= 400 HZ, `v = 340 m//s` (a) When train APPROACHES the platform, `v_(s) = 10 m//s` So, required frequency `=v/(v-v_(s))xxn=(340xx400)/(340-10)=412.12" Hz"` (b) When train recedes from the platfrom. `v_(s) = 10 m//s` Hence, required frequency `=v/(v-v_(s))xxn=(340xx400)/(340+10)= 388.6" Hz"` (ii) The SPEED of sound in both the cases is same. |
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| 11. |
Fig. show a conical pendulum. If the length of the pendulum is l, mass of die bob is m and thetais the angle made by the string with the vertical show that the angular momentum of the pendulum about the point of support is: L = sqrt((m^(2)gl^(3) sin^(4)theta)/(cos theta)) |
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Answer» Solution :When the mass m is at the top of the wedge the component of the weight parallel to the sloping side provide the necessary centripetal force. `MG sin THETA = (mv^(2))/L , v= sqrt(LG sin theta)` |
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| 12. |
Assertion If angle between a and b is 30^(@) . Then angle between 2a and -(b) /(2) will be 150^(@) ReasonSign of dot product of two vectors tells you whether angle between two vectors is acute or obtuse . |
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Answer» If both Assetion and REASON are CORRECT but Reason is the correct explanation of Assertion. 
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| 13. |
Two satellites are at different heights from the surface of earth. Which would have greater velocity? |
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Answer» Solution :ORBITAL velocity, `v_(0)=sqrt((GM)/(R+h))` Clearly, the SATELLITE revolving at smaller height h from the SURFACE of the earth will have a greater velocity. |
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| 14. |
Which one of the following can also act as a lubricant in the machines? |
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Answer» IRON FILLINGS |
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| 15. |
A metre stick is balanced on a knife edge at its centre when two coins, each of mass 5g are put one on top of the other at the 12cm mark. The stick is found to be balaced at 45cm What is the mass of the metre stick ? |
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Answer» Solution :Since stick is in ROTATIONAL equilibrium, the total torque of all forces about the RESULTANT .R. is ZERO. Taking the turning effects about the point of action of the resultant .R. we have `10gxx33=mgxx5` on SOLVING `m=66g` 
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| 16. |
A student says that he had applied a force F= - k/x on a particle and the particle moved in simple harmonic motion. He refuses to tell whether k is a constant or not. Assume that he was worked only with positive x and no other force acted on the particle |
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Answer» As X INCREASES K increases |
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| 17. |
Why do we feel cooler under the fan? |
| Answer» Solution :The air BREEZE PRODUCED by the FAN HELPS in evaporating our perspriration.Heat required for this is observed from our BODY .so we feel cooler under the fan | |
| 18. |
A ring is cut from a platinum tube having 10 cm internal and 11 cm external diameter. It is supported horizontally from a pan of balance o that it comes in contact with water in a glass vessel. What is the surface tension of water if an extra, 4. 752gram weight is required to pull it away from water? ( g= 10 m//s^(2) ): |
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Answer» `7.2 XX 10^(-2) "N/m"` |
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| 19. |
Describe Simple Harmonic Motion as a projection of uniform circular motion. The projection of uniform circular motion on a diameter of SHM |
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Answer» Solution :Consider a particle of mass m moving with uniform speed v along the circumference of a circle whose radius is r in anti-clockwise direction (as shown in figure). Let us assumethat the origin of the coordinate system coincides with the particle at any instant of time t, then `theta=omegat`. By projecting the uniform circular motion on its diameter gives a simple harmonic motion. This means that we can ASSOCIATE a MAP (or a relationship) between uniform circular (or revolution) motion to vibratory motion. Conversely, any vibratory motion or revolution can be mapped to uniform circular motion. In other words, these two motions are similar in NATURE. Let us first project the position of a particle moving on a circle, on to its vertical diameter or on to a line parallel to vertical diameter as shown in figure. Similarly, we can do it for horizontal axis or a line parallel to horizontal axis.  As a specific example, consider a spring mass system (or oscillation of PENDULUM). When the spring moves up and down (or pendulum moves to and fro), the motion of the mass or bob is mapped to points on the circular motion. Thus, if a particle undergoes uniform circular motion then the PROJECTION of the particle on the diameter of the circle (or on a line parallel to the diameter) traces straight line motion which is simple harmonic in nature. The circle is known as reference circle of the simple harmonic motion. The simple harmonic motion can also be defined as the motion of the projection of a particle on any diameter of a circle of reference. |
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| 20. |
For the following situation which of the followingis correct When a car takes a turn on the roadthe centripetal forceis provided by |
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Answer» weightof the car |
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| 21. |
A particle is projected from the ground with an initial speed of v at an angle theta with horizontal . The average velocity of the particle between its point of projection and highest point of trajectory is : |
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Answer» `V/2 SQRT(1+2 cos^(2) theta)` |
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| 22. |
In the givenv-t graph, the distance travelled by the body in 5 second will be . |
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Answer»
The equation of given LINE is , ` v=- v_0/x_0 x = v_0` Differentiatng it w.tr.t. t, we have ` (dv)/(DT)=- v-0/x_0 (DX)/(dt)` or ` a=- v_0 /x_0 v` ` =- v-0 /x_0 ( - v_0/x_0 x + v_0 ) = v_0^2/x_0^2 x - v_0^@/x_0` It is an equation of straight line between (a) and (x) with positive slope ` (=(v_0^2)/x_0^20` and NEGATIVE intercept ` ( = - ( v_0^2/x_0)`. |
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| 23. |
An ideal system can be brought from stage A to B through Four paths as shown in the figure. The energy given to the system is minimum is: |
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Answer» path ACB work is minimum for AFB `rArr TRIANGLE Q_(AFB)` is minimum |
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| 24. |
If the Poissions ratio of a substance is 0.25 then the ratio of its Youngs modulus and rigidity modulus is |
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Answer» `2//5` |
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| 25. |
A satellite is revolving near the earth's surface. Its orbital velocity depends on its mass 'm' as |
| Answer» ANSWER :A | |
| 26. |
A ball strikes a wall with a velocity vec(u) at an angle theta with the normal to the wall surface and rebounds from it at an angle beta with the surface. Then : |
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Answer» `(theta + BETA)` is equal to `90^(@)` is wall is smooth |
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| 27. |
Refer to figure. Let DeltaU_(1)and DeltaU_(2)be thechange in internal energy in processes A and B respectively,DeltaQ be the net heat given to the system in process A+B and DeltaWbe the net work done by the system in the process A+B. a) DeltaU_(1)+DeltaU_(2)=0 b) DeltaU_(1)-DeltaU_(2)=0 c) DeltaQ-DeltaW=0 d) DeltaQ+DeltaW=0 |
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Answer» only a,B are CORRECT |
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| 28. |
If vec(P).vec(Q) = 0, then what is the angle between vec(P) and vec(Q) ? |
| Answer» SOLUTION :`90^(@)` | |
| 29. |
The critical angle for refraction from glass to air is 30^@ and that from water to air is 37^@ Find the critical angle for refraction from glass to water. |
| Answer» Answer :A | |
| 30. |
Find the time period of small oscillations of the following systemA uniform disc of mass m and radius r suspended through a point r/2 away from the centre . |
| Answer» SOLUTION :`2PI SQRT((3R)/(2G))` | |
| 31. |
The equations of motion of a projectile are given by x = 36 metre and 2y = 96t - 9.8 t^(2) metre. The angle of projection is |
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Answer» `SIN^(-1)((4)/(5))` |
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| 32. |
30 gms of water at 30^@Cis in a beaker. Which of the following, when added to water, will have greatest cooling effect? (Specific heat of copper = 0.1 "cal/gm"^@C ) |
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Answer» 100 gms of WATER at `10^@C` |
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| 33. |
A cylinder contains an ideal gas at a pressure of two atmospheres, the volume being 5 litres at a temperature of 250 K. The gas is heated at constant volume to a pressure of 4 atmospheres and then at constant pressure to a temperature of 650 K. Calculate the total heat input during these processes. For the gas C_v = 21Jmol^(-10) C^(-1) . The gas is then cooled at constant volume to its original pressure and then at constant pressure to its original volume. Find the total heat output during these processes and the total work done by the gas in the whole cyclic process. |
| Answer» SOLUTION :TOTAL heat input = 4701 J, Total heat output=4397 J, WORK DONE = 304 J | |
| 34. |
If the angle between two vectors of equal magnitude P is thetathe magnitude of the difference of the vectors is |
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Answer» `2P "COS" (THETA)/(2)` |
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| 35. |
What do you mean by phase of a wave ? |
| Answer» SOLUTION :The PHASE of a harmonic is a quantity that gives COMPLETE information of the WAVE at any TIME and at any position . | |
| 37. |
The centre of mass of an extended body on the surface of the earth and its centre of gravity |
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Answer» are ALWAYS at the same POINT for any size of the BODY |
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| 38. |
Liquid is stick to the glass then angle of contact for liquid glass will be obtain …..(acute /obtuse) |
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Answer» |
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| 39. |
Device used to measure very high temperature is ……………….. . |
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Answer» PYROMETER |
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| 40. |
At a height H from the surface of the earth, the total energy of a satellite is equal to the potential energy of a body of equal mass at a height of 3R from the surface of earth (RRadius of the earth). The value of H is |
| Answer» Answer :B | |
| 41. |
Two blocks with heat capacities C_(1) and C_(2) are connected by a rod of length l, cross-sectional area Aand heat conductivity K. Initial temperature difference between the two blocks is T_(0). Assuming the entire system to be isolated from surroundings heat capacity of the rod to be negligible the temperature difference between the blocks as a function of time |
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Answer» `T_(0)E^(-KA((C_(1)C_(2))/(C_(1)-C_(2)))t)` |
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| 42. |
For humans, minimum wavelength of sound wave in the audible range is nearly…… |
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Answer» SOLUTION :`v = flamda = ` constant =332 m/s `therefore F _(MAX) lamda_(min) 332` `therefore lamda_(min) = (332)/(f _(max)) = (332)/(20000) = 0.01 166 m = 1. 66 cm` |
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| 43. |
A 7 kg shell kept at rest suddenly splits up into three parts. If two parts of mass 3 kg each are found flying due north and cast with a velocity of 3 m/s each, what is the velocity of the third part after explosion ? |
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Answer» 9 m/s DUE north-east |
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| 44. |
The angular velocity and amplitude of a simple pendulum are 'w' and A respectively. At a displacement 'x'. If its KE is T' and PE is 'U' then the ratio of "T" to 'U' is |
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Answer» `(X^(2)W^(2))/(A^(2)-w^(2)x^(2))` |
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| 45. |
Distinguish the radiation and convection methods of heat transfter. |
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Answer» |
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| 46. |
"A wrench of longer arm as compared to a wrench of shorter arm is preferred." Why? |
| Answer» SOLUTION :`vectau = vecr XX vecF`. For the same VALUE of `vecF`, the value of `vectau`will be high when`vecr` is high so.... | |
| 47. |
A block of mass m is given an initial downward velocity v_(0) and left on inclined place ( coefficient of friction =0.6). The block will |
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Answer» continue of move down the plane with constant velocity `v_(0)`  SINCE ,`f_("max")gt mg sin theta` Block will decelerate and come to rest. |
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| 48. |
Obtain the ratio of maximum acceleration and maximum velocity of a SHM particle. |
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Answer» Solution :MAXIMUM ACCELERATION of a SIMPLE harmonic oscillator `a_("max") = A OMEGA^(2)` and maximum velocity `v_("max")= A omega` Ratio `(a_("max"))/(v_("max"))= (A omega^(2))/(A omega )= omega`. |
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| 49. |
The error in the measurement of the length of a simple pendulum is 0.1% and the error in the time period is 2%. What is the possible percentage of error in the physical quantity having the dimensional formula LT^(-2). |
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Answer» `1.1%` |
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| 50. |
One end of U-tube containing mercury is connected to a suction pump and the other end to atmosphere. A small pressure difference is maintained between the two columns. Show that, when the suction pump is removed, the column of mercury in the U-tube executes simple harmonic motion. |
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Answer» Solution :The restoring force, F = - weight of mercury column at height 2y = -(VOLUME) `xx` DENSITY `xx` g = `-(Axx2yxxrhoxxg)=-2Arhogy` where A = area of cross-section of the tube, `RHO` = density of mercury. Force CONSTANT, `k=-F/y=2Arho*g` So, time period `T=2pisqrt(m/k)=2pisqrt(m/(2Arhog))` Let L = length of the whole mercury column. Therefore, mass of mercury, m = volume `xx` density = `ALrho` `therefore" "T=2pisqrt((ALrho)/(2Arhog))=2pisqrt(L/(2g))` where L is the total length of mercury column = 2h, h is the height of mercury column in U-tube. It shows that mercury column executes SHM. |
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