# NCERT Class 11 Physics Multiple Choice Questions(MCQs) & Answers

NCERT Class 11 Physics Multiple Choice Questions(MCQs) & Answers NCERT Class 11 Physics QUESTIONS

# NCERT Class 11 Physics Multiple Choice Questions(MCQs) & Answers

21 The electric potential V at any point O (x, y, z all in metres) in space is given by V = 4x² volt. The electric field at the point (1 m, 0, 2 m) in volt/metre is
A 16 along positive z-axis
B 8 along negative x-axis
C 8 along positive x-axis
D 16 along negative x-axis

22 If a unit positive charge is taken from one point to another over an equipotential surface, then
A no work is done.
B work done is constant.
C work is done on the charge.
D work is done by the charge.

23 A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V. The potential at the centre of the sphere is
A 0 V
B 10 V
C Same as at point 5 cm away from the surface
D Same as at point 25 cm away from the surface

24 The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is
A proportional to the square root of the distance between the plates.
B linearly proportional to the distance between the plates.
C independent of the distance between the plates.
D inversely proportional to the distance between the plates.

Answer: independent of the distance between the plates.
25 A charged particle is moving in a cyclotron, what effect on the radius of path of this charged particle will occur when the frequency of the ratio frequency field is doubled?
A It will remain unchanged.
B It will be increased by four times.
C It will be halved.
D It will also be doubled.

26 Two a-particles have the ratio of their velocities as 3 : 2 on entering the field. If they move in different circular paths, then the ratio of the radii of their paths is
A 3 : 2
B 4 : 9
C 2 : 3
D 9 : 4

27 A charged particle is moving on circular path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes
A 8 times
B 4 times
C 2 times
D None of these

28 Which one of the following is correct statement about magnetic forces?
A Magnetic forces always obey Newton’s third law.
B Magnetic forces do not obey Newton’s third law.
C For very high current, magnetic forces obey Newton’s third law.
D Inside low magnetic field, magnetic forces obey Newton’s third law.

Answer: Magnetic forces do not obey Newton’s third law.
29 In an inertial frame of reference, the magnetic force on a moving charged particle is Its value in another inertial frame of reference will be
A remained same
B changed due to change in the amount of charge
C changed due to change in velocity of charged particle
D changed due to change in field direction

Answer: changed due to change in velocity of charged particle
30 Curie law xT = constant, relating magnetic susceptibility (x) and absolute temperature (T) of magnetic substance is obeyed by
A all magnetic substances.
B paramagnetic substances.
C diamagnetic substances.
D ferromagnetic substances.