Electromagnetics Field (3140912) MCQs

MCQs of Magnetic forces, materials and inductance

Showing 41 to 50 out of 171 Questions
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41.
When a magnet is in motion relative to a coil the induced emf does not depend upon
(a) Resistance of the coil
(b) Motion of the magnet
(c) Number of turns of the coil
(d) Pole strength of the magnet
Answer:

Option (a)

42.
One maxwell is equal to
(a) 10×10–8 Wb
(b) 10×108 Wb
(c) 1 Wb
(d) 10 Wb
Answer:

Option (a)

43.
When two ends of a circular uniform wire are joined to the terminals of a battery, the field at the center of the circle
(a) Will be zero
(b) Will be infinite
(c) Will depend on the amount of emf applied
(d) Will depend on the radius of the circle
Answer:

Option (d)

44.
Susceptibility is positive for
(a) Nonmagnetic substances
(b) Diamagnetic substances
(c) Ferromagnetic substances
(d) None of above
Answer:

Option (c)

45.
The most effective and quickest way of making a magnet from soft iron is by
(a) Placing it inside a coil carrying current
(b) Induction
(c) Use of permanent magnet
(d) Rubbing with another magnet
Answer:

Option (a)

46.
The commonly used material for shielding or screening magnetism is
(a) Copper
(b) Aluminum
(c) Soft iron
(d) Brass
Answer:

Option (c)

47.
If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle will start rotating with a velocity
(a) Less than that of disc but in opposite direction
(b) Equal to that of disc and in the same direction
(c) Equal to that of disc and in the opposite direction
(d) Less than that of disc and in the same direction
Answer:

Option (d)

48.
A permanent magnet
(a) Attracts some substances and repels others
(b) Attracts all paramagnetic substances and repels others
(c) Attracts only ferromagnetic substances
(d) Attracts ferromagnetic substances and repels all others
Answer:

Option (a)

49.
The retentivity of material is useful for the construction of
(a) Permanent magnets
(b) Transformers
(c) Nonmagnetic substances
(d) Electromagnets
Answer:

Option (a)

50.
Relative permeability of which materials is not constant?
(a) Diamagnetic
(b) Paramagnetic
(c) Ferromagnetic
(d) Insulating
Answer:

Option (c)

Showing 41 to 50 out of 171 Questions
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