Moving Charges and Magnetism Class 12 Physics MCQs Pdf
37. The correct plot of the magnitude of magnetic field \(\vec{B}\) vs distance r
from centre of the wire is, if the radius of wire is R
Answer
Answer: b
38. The nature of parallel and anti-parallel currents are
(a) parallel currents repel and antiparallel cur¬rents attract.
(b) parallel currents attract and antiparallel cur-rents repel.
(c) both currents attract. ’
(d) both currents repel.
Answer
Answer: b
39. The magnetic moment of a current I carrying circular coil of radius r and number
of turns N varies as
(a) \(\frac{1}{r²}\)
(b) \(\frac{1}{r}\)
(c) r
(d) r²
Answer
Answer: d
40. A short bar magnet has a magnetic moment of 0. 65 J T-1, then the
magnitude and direction of the magnetic field produced by the magnet at a distance 8
cm from the centre of magnet on the axis is
(a) 2.5 × 10-4 T, along NS direction
(b) 2.5 × 10-4 T along SN direction
(c) 4.5 × 10-4 T, along NS direction
(d) 4.5 × 10-4 T, along SN direction
Answer
Answer: b
41. A current carrying loop is placed in a uniform magnetic field. The torqe acting
on it does not depend upon
(a) area of loop
(b) value of current
(c) magnetic field
(d) None of these
Answer
Answer: d
42. In a moving coil galvanometer the deflection (Φ) on the scale by a pointer
attached to the spring is
Answer
Answer: c
43. A moving coil galvanometer can be converted into an ammeter by
(a) introducing a shunt resistance of large value in series.
(b) introducing a shunt resistance of small value in parallel.
(c) introducing a resistance of small value in series.
(d) introducing a resistance of large value in parallel.
Answer
Answer: b
44. The conversion of a moving coil galvanometer into a voltmeter is done by
(a) introducing a resistance of large value in series.
(b) introducing a resistance of small value in parallel.
(c) introducing a resistance of large value in parallel.
(d) introducing a resistance of small value in series.
Answer
Answer: a
45. Deflection produced in a galvanometer when a unit current flows through it is known as _________ .
Answer/Explanation
Answer:
Explaination: current sensitivity.
46. A moving coil galvanometer can be converted into voltmeter by connecting a large resistance R in _________ with it.
Answer/Explanation
Answer:
Explaination: series
47. Maximum torque acts on a current carrying coil when it is suspended in magnetic field such that its plane is _________ to magnetic field.
Answer/Explanation
Answer:
Explaination: parallel
48. An ammeter is _________ resistance galvanometer.
Answer/Explanation
Answer:
Explaination: low