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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 projectile is thrown at an angle of 30^(@) with a velocity of 10 m/s. the change in velocity during the time interval in which it reaches the highest point is |
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Answer» 10 m/s |
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| 2. |
The temperature of sink of Carnot engine is27^(@)C. Efficiency of engine is 25%. Then temperature of source is |
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Answer» `227^(@)C` |
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| 3. |
A projectile, launched into the air, suddenly explodes. Where docs the centre of mass of the fragments touch the ground ? |
| Answer» Solution :The CENTRE of mass of the fragments touches the ground at the POINT when the UNEXPLODED projectile WOULD have touched. | |
| 4. |
A ball is dropped from a height h on to a floor. If, in each collision, its speed becomes e times of its striking vaue (a) Find the total change in momentum of the ball (b) Find the average force exerted by the ball on the floor. |
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Answer» Solution :(a) Change in momentum in I COLLISION `=mv_(1)- (-mv_(0)) = m(v_(1) + v_(0))` Change in momentum in II collision `=m (v_(2) + v_(1))` Change in momentum in `n^(th)` collision `= m(v_(n) + v_(n-1))` Adding these all, total change in momentum of the ball is `Delta p= m [v_(0) + 2v_(1) + ...+ 2v_(n-1) + v_(n)]` or `Delta p= mv_(0) [1 + 2E + 2e^(2) + ....] [ " as " v_(1)= ev_(0), v_(2) = e^(2) v_(0)...]` `Delta p= mv_(0)[1 + 2e ((1)/(1-e))]= m sqrt(2gh) [1 + e)/(1-e)]` ..(1) (b) Now as `vec(F )= ((vec(dp)),(dt)) "so", F_(av)= ((Delta p),(Delta T))` we KNOW `Delta T = sqrt((2h)/(g)) ((1 + e)/(1-e))` From (1) `Delta p= m sqrt(2gh) [(1 + e)/(1-e)]` `F_(av)= m sqrt(2gh) [(1 + e)/(1-e)] xx sqrt((g)/(2h)) [(1-e)/(1+e)] = MG` |
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| 5. |
In one dimensional motion, instantaneous speed V satisfies 0leVltV_(0) |
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Answer» The displacement in time T must always take nonnegative values |
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| 6. |
A temperature is measured by a constant volume gas thermometer |
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Answer» T is independent of the GAS USED for all pressures |
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| 7. |
Passage - II : A solid cylinder of mass m and radius R and that of plank M placed on smooth horizontal surface. Given that sufficient friction is present between cylinder and the plank surface to prevent sliding of cylinder. If plank is pulled force F. answer the following The acceleration of the cylinder is |
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Answer» `(F)/(M+3m)` |
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| 8. |
Passage - II : A solid cylinder of mass m and radius R and that of plank M placed on smooth horizontal surface. Given that sufficient friction is present between cylinder and the plank surface to prevent sliding of cylinder. If plank is pulled force F. answer the following The tension in the string is |
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Answer» `(MF)/(M+3m)` |
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| 9. |
Passage - II : A solid cylinder of mass m and radius R and that of plank M placed on smooth horizontal surface. Given that sufficient friction is present between cylinder and the plank surface to prevent sliding of cylinder. If plank is pulled force F. answer the following The magnitude of friction between cylinder and plank is |
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Answer» `(2mF)/(M+3m)` |
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| 10. |
In magnetic field, for a charged particle (in motion) match the following table |
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Answer» <P> |
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| 11. |
A force F is applied on a square plate of side L. If percentage erroe in determine of L is 2% and that in F 4% the permissible error in pressure is….. |
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Answer» 0.02 `(DELTAP)/(P)XX100=((DeltaF)/(F)xx100)+2((DELTAL)/(L)xx100)=4%+2(2%)` `(DeltaP)/(P)xx100=8%` |
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| 12. |
A man is spinning in the gravity free - space changes the shape of the body by spreading his arms. By doing this he can change his (a) moment of inertia(b) angular momentum(c ) angulat velocity(d) rotational kinetic energy Which one of the following are correct? |
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Answer» a,B and c |
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| 13. |
What is the value of absolute zero temperature on Fahrenheit scale? |
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Answer» |
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| 14. |
In a sinusoidal wave,the time required for a particular point to move from maxiumum displacement to zero displacement is 0.170 s.The frequency of the wave is |
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Answer» 1.47 Hz |
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| 15. |
A circular current carrying loop is placed in x-y plane as shown in figure. A uniform magnetic field B=B_(0)hatK is present in the region. Match the following. |
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Answer» <P> |
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| 16. |
(A) : Work done in moving a body of mass .m. on a horizontal surface of coefficient of friction mu along semi circular path of radius .r. by friction is pi mu mgr.(R ) : Friction always opposes relative motion. |
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Answer» Both (A) and (R ) are TRUE and (R ) is the CORRECT EXPLANATION of (A) |
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| 17. |
A uniform rod is fixed at one end to a rigid support, its temperature is gradually increased the representation of graph strain (e) versus increment in temperature Delta theta is |
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Answer» d |
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| 18. |
The bob of a pendulum is released from a horizontal position. If the length of the pendulum is 1.5m, what is the speed with which the bob arrives at the lowermost point, given that it dissipated 5% of its initial energy against air resistance ? |
| Answer» Answer :A | |
| 19. |
If the velocity of light, acceleration due to gravity and normal pressure are chosen as fundamental units, find the unit of mass, length and time. Given that velocity of lightc=3 xx 10^(8)ms^(-1) g=10ms^(-2) and the normal atmospheric pressure P=10^(5) Nm^(-2) |
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Answer» SOLUTION :`[C]=L^(1)T^(-1)=3xx10^(8)ms^(-1) .....(1)` `[g]=L^(1)T^(-2) == 10 ms^(-2) .....(2)` `[P]=M^(1)L^(-1)T^(-2)=10^(5)Nm^(-2) ....(3)` Now, we.ll find out value of M,L, &T. `:.(L^(1)T^(-1))/(L^(1)T^(-2))=([C])/([g])=(3xx0^(8))/(10)` `:.T^(1)=3xx10^(7)s...(i)` Now `[C]=(L^(1))/(T^(1)) rArr L^(1)=[C]xxT^(1)` `=3xx10^(8)xx10^(15)m...(ii)` `[P]M^(1)xxL^(-1)T^(-2)=10^(5)` `:.M^(1)=([P])/(L^(-1)T^(-2))=[P]L^(1)T^(2)` `=10^(5)xx9xx10^(15)xx9xx10^(14)` (From equatio (i), (ii)) `:. M^(1)=81xx10^(34) KG (ii)` |
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| 20. |
A uniform thin rod of length 50 cm is bent so as to form the five sides of a regular hexagon. The distance of centre of mass from either end is |
| Answer» Answer :B | |
| 21. |
Planck.s constant (h), speed of light in vacuum (c) and Newton.s gravitational constant (G) are three fundamental constants. Which of the following combination of these has the dimension of length ? |
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Answer» `SQRT((HG)/( C^(3//2) )` |
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| 22. |
Consider the statement (A) and (B) and identify the correct answer. A: First law of thermodynamics specifies the condition underwhich a body can use its heat energy to produce the work. B: Second law of thermodynamics states that heat always flows from hot body to cold body by itself |
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Answer» Both (A) and (B) are TRUE |
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| 23. |
Two seconds after projection, a projectile is moving at 30^@above the horizontal. After one more second it is moving horizontally. If g = 10ms^(-2), the velocity of projection is |
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Answer» `10 SQRT3 MS^(-1)` |
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| 24. |
Calculate the amplitude, angular frequency, frequency, time period and initial phase for the simple harmonic oscillation given below: (a) y=0.3sin(40pit+1.1) (b) y=2cos(pit) (c ) y=3sin(2pit-1.5) |
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Answer» Solution :Simple harmonic oscillation EQUATION is `y=Asin(omegat+phi_(0))ory=Acos(omegat+phi_(0))` (a) For the wave, `y=0.3sin(40pit+1.1)` Amplitude is `A=0.3` unit Angular frequency `omega=40pi` rad `s^(-1)` Frequency `f=(omega)/(2pi)=(40pi)/(2pi)=20Hz` Time period `T=(1)/(f)=(1)/(20)=0.05s` Initial phase is `phi_(0)=1.1` rad (b) For the wave, `y=2cos(pit)` Amplitude is `A=2` unit Angular frequency `omega=PI` rad `s^(-1)` Frequency `f=(omega)/(2pi)=(pi)/(2pi)=0.5Hz` Time period `T=(1)/(f)=(1)/(0.5)=2s` Initial phase is `phi_(0)=0` rad (C ) For the wave, `y=3sin(2pit+1.5)` Amplitude is `A=3` unit Angular frequency `omega=2pi` rad `s^(-1)` Frequency `f=(omega)/(2pi)=(2pi)/(2pi)=1Hz` Time period `T=(1)/(f)=(1)/(1)=1S` Initial phase is `phi_(0)=1.5` rad |
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| 25. |
A body of mass 2 kg is attached to a weightless string wound round a cylinder of mass 5 kg and radius 50 cm. the body is allowed to fall. Calculate (i) tension in the string (ii) acceleration with which the body falls. |
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Answer» |
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| 26. |
For large and equal values of d and h, which is greater g_n or g_d ? Give reason for your answer |
| Answer» SOLUTION :For a large VALUE of h and d (COMPARABLE with radius of earth) value at a DEPTH d is LESS than g value at aheight ‘h.. | |
| 27. |
To lift a motor car from a ditch, one end of a rope ABCisattached to a point A of a tree and the other end is tied at a point C of the car. At the mid-point B of the rope ,a pull of 200 kg -wt is applied at right angles to AC. If angleABC=120^(@) , find the tension in the rope. |
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Answer» |
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| 28. |
The position-time graph of a body of mass 0.04kg is shown in the figure. The time between two consecutive impulses received by the body and the magnitude of each impulse is |
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Answer» `4SEC, 4xx10^(-4)kgm//s` |
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| 29. |
Let the angle between two nonzero vectors vec(A) and vec(B) be 120^(@) and its resultant be vec(C). |
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Answer» C must be EQUAL `|A-B|` |
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| 30. |
Find the centre mass of the following L and T-shaped planks with reference to the frameindicated in figure 6.10. |
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Answer» |
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| 31. |
In the above questin, the total distance covered by the body in 8 seconds is. |
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Answer» 9m |
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| 32. |
If an engine delivers 9.5 xx 10^(6) J of work per hour and absorbs 6.2 xx 10^(7) J of heat per hour, then the amount of heat wasted per hour is |
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Answer» `6.95 XX 10^(7) J` |
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| 33. |
The velocites of a body executing SHM at displacement .a. and .b. are .b. and .a. respectively. The amplitude of S.H.M will be |
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Answer» a+B |
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| 34. |
A particle is projected from a tower as shown in figure, then find the distance from the foot of the tower where It will strike the ground. (g = 10 m//s^(2)) |
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Answer» Solution :`s = u t + (1)/(2) a t^(2)` `1500 = (500)/(3) sin 37 + (1)/(2) 10 xx t^(2)` `1500 = (500)/(3) xx (3)/(5) t + 5T^(2)` `300 = 20t + t^(2)` On solving, t = 10 s `therefore` horizontal distance `= u cos theta. T` `= (500)/(3) xx (4)/(5) xx 10 = (4000)/(3)m` 
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| 36. |
Planets moving around sun and each planet having satellites moving around them is an example of |
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Answer» RIGID system |
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| 37. |
Consider the following statement 'A and 'B' and identify the correct answer A: In an elastic collision, if a body suffers a head on collision with another of same mass at rest, the first body comes to rest while other starts moving with the velocity of first one. B: Two bodies of equal masses suffering a head on elastic collision exchange their velocities |
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Answer» Both A and B are TRUE |
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| 38. |
A uniform rod BC with length a is attached to a light string AC. End A of the string is fixed to the ceiling and the end B of the rod is on a smooth horizontal surface. B is exactly below point A and length AB is b (a lt b lt 2a). The system isreleased from rest and the rod begins to slide. Find the speed of the centre of the rod when the string becomes vertical. |
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Answer» |
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| 39. |
The radius of gyration of a ring about the tangent perpendicular to its plane is…………… |
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Answer» `(R )/(2)` `=MR^(2)+MR^(2)` `I=2MR^(2)` `MK^(2)=2MR^(2)` `therefore k=sqrt(2)R` |
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| 40. |
An iron tyre is to be fitted on a wooden wheel 0.1m in diameter. The miameter of the tyre is 6 mm smaller than that of the wheel. The tyre should be heated by a temperature of (coefficient of volume expansion or iron is 3.6xx10^(-5)//^(@)C)………….. . |
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Answer» `167^(@)C` `0.006=0.994xx3.6xx10^(-5)xxDeltat` `Deltat=(0.006)/(0.994xx3.6xx10^(-5))=167^(@)C` |
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| 41. |
Two small drops of mercury each of radius r coalesce to form a single large drop of radius R. The ratio of the total surface energies before and after the change is …… |
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Answer» `1:2^((1)/(3))` Total volume of N drops = volume of large drop. Each small drop has radius r , then `n(4)/(3)pir^(3)=(4)/(3)piR^(3)` `thereforeR=n^((1)/(3))r` [Here n=2] `thereforeR=2^((1)/(3))r` (The ratio of surface ENERGIES of small drops and large drop) `(E_(i))/E_(f)=(2(4pir^(2)T))/(4piR^(2)T)` `=(2r^(2))/(R^(2))=(2r^(2))/(R^((2)/(3)r^(2)))` `=(2)/(2^((2)/(3)))=(2^((1)/(3)))/(1)` |
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| 42. |
A metal disc has a hole in it. When the disc is heated, the size of the hole _________ |
| Answer» Solution :EXPANSION is always outward, therefore the hole SIZE INCREASED on heating. | |
| 43. |
Show that Dopple effect is greater when the source approaches the observe than when the observer approaches the source with the same speed. |
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| 44. |
A solid sphare of mass 2kg is resting inside a cube as shown in the figure . The cube is moving with a velocity . Here t is in second . All surfaces are smooth . The sphare is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. |
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Answer» Solution :`v=5ti+2tj, VECA=(DV)/(dt)=5i+2j` `F=ma_(X)hati+m(g+a_(y))hatj,F=2(5i)+2[10+2]hatj,` `F=10i + 24j, F=SQRT(100+576)=sqrt(676)=26N` |
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| 45. |
(A) : Relative velocity is zero when two bodies are moving opposite to each other with same velocity ( R) : Relative velocity of a body does not depend on direction of motion. |
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Answer» Both (A) and ( R) are TURE and ( R) is the correct explanation of (A) |
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| 46. |
A satellite is orbiting around the Earth in a circular orbit with velocity v. If m is the mass of the satellite, its total energy is ........ . |
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Answer» `MV^(2)` |
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| 47. |
A particle of mass 2 kg is on a smooth horizontal table and moves in a circular path of radius 0.6m. The height of the table from the ground is 0.8 m. If the angular speed of the particle is 12 rad s^(-1) , the magnitude of its angular momentum about a point on the ground right under the centre of the circle is |
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Answer» `11.52 KG m^(2)//s^(-1)` |
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| 48. |
Therelationet= sqrt(3x) +6 describes the displacementof a particle in one direction where x is in metres and t in sec. The displacement, when velocity is zero, is |
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Answer» 24 METRES |
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| 49. |
If vecA=3i++4j"and" vecB=7i+24j, then the vector having the same magnitued as vecBand parallet to vecA is |
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Answer» |
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| 50. |
A ladder is leaned against a smooth wall and it is allowed to slip on a frictionless floor. Which figure represent trace of its centre of mass? |
| Answer» Answer :C | |
