Electromagnetics Field (3140912) MCQs

MCQs of Magnetic forces, materials and inductance

Showing 131 to 140 out of 171 Questions
131.
The self inductance of two coils are 8 mH and 18 mH. If the co-efficients of coupling is 0.5, the mutual inductance of the coils is
(a) 4 mH
(b) 5 mH
(c) 6 mH
(d) 12 mH
Answer:

Option (c)

132.
Two coils have inductance of 8 mH and 18 mH and a co-efficient of coupling of 0.5. If the two coils are connected in series aiding, the total inductance will be
(a) 32 mH
(b) 38 mH
(c) 40 mH
(d) 48 mH
Answer:

Option (b)

133.
A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities i.e. area, length etc. remaining the same, the inductance will be
(a) 6 mH
(b) 14 mH
(c) 24 mH
(d) 48 mH
Answer:

Option (d)

134.
Two coils have self-inductance of 10 H and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be
(a) 6 H
(b) 8 H
(c) 12 H
(d) 24 H
Answer:

Option (c)

135.
In case all the flux from the current in coil 1 links with coil 2, the co-efficient of coupling will be
(a) 2
(b) 1
(c) 0.5
(d) Zero
Answer:

Option (b)

136.
A coil with negligible resistance has 50 V across it with 10 mA. The inductive reactance is
(a) 50 Ω
(b) 500 Ω
(c) 1000 Ω
(d) 5000 Ω
Answer:

Option (d)

137.
A conductor 2 m long moves at right angles to a magnetic field of flux density 1 Tesla with a velocity of 12.5 m/s. The induced emf in the conductor will be
(a) 10 V
(b) 15 V
(c) 25 V
(d) 50 V
Answer:

Option (c)

138.
A conductor carries 125 A of current under 60° to a magnetic field of 1.1 Tesla. The force on the conductor will be
(a) 50 N
(b) 120 N
(c) 240 N
(d) 480 N
Answer:

Option (b)

139.
What will be the force acting on a conductor 3 m long carrying a current of 50 A at right angles to a magnetic field having a flux density of 0.67 Tesla?
(a) 100 N
(b) 400 N
(c) 600 N
(d) 1000 N
Answer:

Option (a)

140.
The co-efficient of coupling between two air core coils depends on
(a) Self-inductance of two coils only
(b) Mutual inductance between two coils only
(c) Mutual inductance and self inductance of two coils
(d) None of above
Answer:

Option (c)

Showing 131 to 140 out of 171 Questions