MCQ : Set #13

NOTE : Each set contains 30 questions. Time limit is 45 minutes.

1. Maximum reinforcement of two waves is obtained at points with phase difference of...
   

   [A] nπ [B] nπ/2 [C] 2nπ [D] (2n + 1)π/2

2. If 'd' is the width of slit, the diffraction is greater for...
   

   [A] larger d, larger λ  [B] larger d, smaller λ 
   [C] smaller d, larger λ [D] smaller d, smaller λ

3. The SI unit of Planck's constant is...
   

   [A] J [B] J/s [C] J.s [D] J/s.K

4. The energy of an electron depends on...
   

   [A] its distance from the nucleus [B] the diameter of the nucleus 
   [C] its diameter                  [D] its charge

5. Which of the following is not the spectral series obtained in the hydrogen spectrum?
   

   [A] Balmer series [B] Pascal series [C] Pfund series [D] Paschen series

6. The conductivity of a semiconductor can be changed by adding impurities and by...
   

   [A] changing its size [B] changing its shape [C] changing its density [D] irradiation

7. A body falling from rest covers a distance h/2 in the last second of its fall. Then the height h from which it falls is...
   

   [A] 9.8 m [B] 58.28 m [C] 100/√ 2 m [D] 50/√ 2 m

8. The two ends of a train moving with uniform acceleration pass a certain point with velocities v₁ and v₂. The velocity with which the middle point of the train passes the same point is...
   

   [A] √(v12 + v22)/2 [B] √(v12 - v22)/2 [C] √(v22 - v12)/2 [D] (v1 + v2)/2

9. The angle which the vector 3i + 4j makes with X-axis is...
   

   [A] 30° [B] 45° [C] tan-1 (4/3) [D] tan-1 (3/4)

10. Two bodies of equal mass are in uniform circular motion with the same period.If r₁ and r₂ are the radii of their circular paths then the ratio of their centripetal force is...
    

    [A] r12 / r22 [B] r22 / r12 [C] r1 / r2 [D] r2 / r1

11. A ball is dropped from a vertical height 'h' on the ground. If 'e' is the coefficient of restitution then the height to which the ball goes up after it rebounds for n-th time is...
    

    [A] h/(en) [B] h/(e2n) [C] h.(en) [D] h.(e2n)

12. Water falls on the blades of a turbine at the rate of 10 kg/s from a height of 10 m. The power delivered to the turbine is...(take g = 10 m/s²)
    

    [A] 1 W [B] 1 kW [C] 100 W [D] 100 kW

13. An electric fan has a blade of length l. The fan makes n rotations in one minute. The acceleration of a point on the tip of the blade is...
    

    [A] 4π2.l/n [B] 4π2.l.n2/(60 x 60) [C] 4π2.l.n2/60 [D] 4π2.l/60n

14. A body of mass m slides down an incline and reaches the bottom with velocity v. If a ring of same mass rolls down the same incline then the velocity of the ring at the bottom is...
    

    [A] v [B] 2v [C] v/√ 2 [D] (√ 2)v

15. The gravitational force between two particles of mass 2 kg each separated by a distance 2m is...
    

    [A] 6.67 x 10-11 N [B] 0 [C] 3.335 x 10-11 N [D] 13.34 x 10-11 N

16. The period of revolution of a satellite in a circular orbit of radius r is T. The period of the same satellite in another circular orbit of radius 4r is...
    

    [A] T/4 [B] T/8 [C] 2T [D] 8T

17. If K is Boltzmann's constant, the average kinetic energy of a molecule of a perfect gas is...
    

    [A] 2/3 kT [B] 2.5 kT [C] 3.5 kT [D] 1.5 kT

18. The efficiency of a Carnot engine working between constant high temperature T₁ and constant low temperature T₂ is maximum when...
    

    [A] T1 and T2 are high       [B] T1 is high and T2 is low 
    [C] T2 is high and T1 is low [D] T1 and T2 equal

19. A cooking vessel must have...
    

    [A] high thermal conductivity and high specific heat 
    [B] low thermal conductivity and low specific heat
    [C] high thermal conductivity and low specific heat
    [D] low thermal conductivity and high specific heat

20. The total energy of a particle executing SHM is 100 J.Then the maximum value of kinetic energy is...
    

    [A] 50 J [B] 100 J [C] 25 J [D] 10 J

21. When a mass m is suspended from a spring its period of oscillation is one second. If the mass is reduced to m/2, the new period will be...
    

    [A] 1 second [B] 1/2 second [C] √ 2 second [D] 1/(√ 2) second

22. Which of the following quantities can be considered as the fundamental quantity of a wave?
    

    [A] Velocity [B] Frequency [C] Wavelength [D] Amplitude

23. In a stationary wave, strain is...
    

    [A] maximum at node [B] maximum at antinode 
    [C] minimum at node [D] equal at nodes and antinodes

24. Dimensions of momentum are...
    

    [A] M1L1T1 [B] M1L1T-2 [C] M1L-1T-2 [D] M1L-1T-1

25. When a 1-N force acts on a 1-N object that is able to move freely, the object receives...
    

    [A] a speed of 1 m/s           [B] an acceleration of 1.02 m/s2 
    [C] an acceleration of 1 m/s2  [D] an acceleration of 9.8 m/s2

26. The coefficient of static friction for steel on ice is...
    

    [A] 0.1 [B] 0.1 N [C] 0.1 Nm [D] 0.1 N.kg-1

27. The work done in moving an object from A to B against a non-conservative force
    

    [A] cannot be recovered by moving it from B to A
    [B] does not depend on the path taken between A and B 
    [C] is always entirely converted in to  heat 
    [D] disappears forever

28. Car A has mass of 1000 kg and speed of 60 kmph. Car B has mass of 2000 kg and speed of 30 kmph. The kinetic energy of car A is...
    

    [A] half that of car B  [B] equal to that of car B
    [C] twice that of car B [D] four times that of car B

29. Brownian motion increases as...
    

    [A] the particle size increases [B] the viscosity of the medium increases
    [C] the temperature increases   [D] the temperature decreases

30. The equilibrium separation between the molecules corresponds to...
    

    [A] maximum potential energy [B] minimum potential energy
    [C] zero potential energy    [D] zero kinetic energy