MCQs on Moving Coil Galvanometer

MCQs on Moving Coil Galvanometer

Q1: The deflection θ is related to the electric current I in a galvanometer by the relation

1. I ∝ θ
2. I ∝ tan θ
3. I ∝ sin θ
4. I ∝ cos θ

Answer: (a) I ∝ θ

Q2: A moving coil galvanometer carries a current I and the magnetic field B is radial. The coil has N number of turns and an effective area A. The torque acting on the coil of a moving coil galvanometer is given by

1. NA²B²I
2. NABI²
3. NABI
4. N²ABI

Answer: (c) NABI

Q3: The sensitivity of a moving coil galvanometer can be increased by decreasing

1. The number of turns in the coil
2. The area of the coil
3. The magnetic field
4. The couple per unit twist of the suspension

Answer: (d) The couple per unit twist of the suspension

Q4: In ballistic galvanometer, the frame on which the coil is wound is non-metallic. It is

1. To avoid the production of induced e.m.f
2. To avoid the production of eddy currents
3. To increase the production of eddy currents
4. To increase the production of induced e.m.f

Answer: (b) To avoid the production of eddy currents

Q5: The reason the coil is bound over the metallic frame in moving coil galvanometer is

1. The metallic frame helps in oscillation
2. The metallic frame helps in making steady deflection without any oscillation
3. The metallic frame increases the magnetic field
4. None of the above

Answer: (b) The metallic frame helps in making steady deflection without any oscillation

Q6: The deflection in moving coil galvanometer is

1. Inversely proportional to the area of the coil
2. Directly proportional to the torsional constant
3. inversely proportional to the current flowing
4. Directly proportional to the number of turns of the coil

Answer: (d) Directly proportional to the number of turns of the coil

Q7: The pole pieces of the magnet used in a pivoted coil galvanometer are

1. Plane surfaces of a horse-shoe magnet
2. Cylindrical surfaces of a bar magnet
3. Plane surfaces of a bar magnet
4. Cylindrical surfaces of a horse-shoe magnet

Answer: (d) Cylindrical surfaces of a horse-shoe magnet

Q8: A current-carrying rectangular coil placed in a uniform magnetic field. In which orientation will the coil rotate?

1. In any orientation
2. The magnetic field is parallel to the plane of the coil
3. The magnetic field is at 45⁰ with the plane of the coil
4. The magnetic field is perpendicular to the plane

Answer: (d) The magnetic field is perpendicular to the plane

Q9: What is the shape of a magnet in moving coil galvanometer to make the radial magnetic field?

1. Convex cylindrical magnet
2. Horse-shoe magnet
3. Concave cylindrical magnet
4. None

Answer: (c) Concave cylindrical magnet

Q10: Phospher- bronze wire is used in suspension because it has

1. A large couple per unit twist
2. A small couple per unit twist
3. Low conductivity
4. High Sensitivity

Answer: (b) A small couple per unit twist