Q. 1. Dimensions of resistance in an electrical circuit, in terms of dimension of mass M, of length L, of time T and of current I, would be
Sol. Correct choice: (1)
Q. 2. A particle moving along x-axis has acceleration f, at time t, given
are constant. The particle at t = 0 has zero velocity. In the time interval between t = 0 and the instant when f = 0 , the particle’s velocity (vx ) is
Sol.
If they have asked instantaneous velocity when Correct choice: (1)
Q. 3. A car moves from X to Y with a uniform speed vu and returns to Y with a uniform speed vd .The average speed for this round trip is
Sol. In question it must be car moves from X to Y and returns to X.
Correct choice: (2)
Q. 4. A particle starting from the origin (0, 0) moves in a straight line in the (x, y) plane. Its co-ordinates at a later time are . The path of the particle makes with the x-axis an angle of
Sol. Correct choice: (4)
Q. 5. A block B is pushed momentarily along a horizontal surface with an initial velocity V. If is the coefficient of sliding friction between B and the surface, block B will come to rest after a time
Sol. Correct choice: (2)
Q. 6. A vertical spring with force constant K is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d . The net work done in the process is
Sol.
Correct choice: (3)
Q. 7. A wheel has angular acceleration of 3.0 rad/sec2 and an initial angular speed of 2.00 rad / sec. In a time of 2 sec it has rotated through an angle (in radian) of
Sol. Correct choice: (3)
Q. 8.
Sol.
Correct choice: (2)
Q. 9. The position x of a particle with respect to time t along x -axis is given by where x is in metres and t in second. What will be the position of this particle when it achieves maximum speed along the +x direction?
Sol. Correct choice: (3)
Q. 10. A mass of 2.0 kg is put on a flat pan attached to a vertical spring fixed on the ground as shown in the figure. The mass of the spring and the pan is negligible. When pressed slightly and released the mass executes a simple harmonic motion. The spring constant is 200 N/m. What should be the minimum amplitude of the motion so that the mass gets detached from the pan?
Sol. Correct choice: (3)
Q. 11. A particle of mass m moves in the XY plane with a velocity V along the straight line AB. If the angular momentum of the particle with respect to origin O is LA when it is at A and LB when it is at B, then
Sol. Correct choice: (3)
Q. 12. A uniform rod AB of length l and mass m is free to rotate about point A. The rod is released from rest in the horizontal position. Given that the moment of inertia of the rod about , the initial angular acceleration of the rod will be
Sol. Correct choice: (1)
Q. 13. Two satellites of earth, are moving in the same orbit. The mass of is four times the mass of . Which one of the following statements is true?
Sol . As orbital velocity it is independent of mass of satellite Correct choice: (4)
Q. 14. Assuming the sun to have a spherical outer surface of radius r , radiating like a black body at temperature , the power received by a unit surface, (normal to the incident rays) at a distance R from the center of the sun is (where is the Stefan’s constant).
Sol. Power radiated
Correct choice: (1)
Q. 15. An engine has an efficiency of 1/6. When the temperature of sink is reduced by 620C, its efficiency is doubled. Temperature of the source is
Sol. Correct choice: (1)
Q. 16. A black body is at . It emits energy at a rate which is proportional to
Sol. Correct choice: (3)
Q. 17. The frequency of a light wave in a material is and wavelength is 5000Å. The refractive index of material will be
Sol. Correct choice: (4)
Q. 18. The phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is
Sol.
Correct choice: (2)
Q. 19. The particle executing simple harmonic motion has a kinetic energy . The maximum values of the potential energy and the total energy are respectively
Sol. Correct choice: (1)
Q. 20. A particle executes simple harmonic oscillation with an amplitude a . The period of oscillation is T. The minimum time taken by the particle to travel half of the amplitude from the equilibrium position is
Sol. Correct choice: (4)