If a current that varies with time flows through a coil an emf is induced in the coil. The emf produced is directly proportional to the rate of change of current with time. The proportionality constant in the relation between current and emf is called Inductance.
Q1: Mutual inductance between two magnetically coupled coils depends on
- Permeability of the core material
- Number of turns of the coils
- The cross-sectional area of their common core
- All of the above
Answer: (d) All of the above
Q2: What will be the inductance if the iron core is removed from the iron cored coil to make it air-cored coil?
- The same
Answer: (b) Less
Q3: Higher the self-inductance of a coil
- Lesser its weber-turns
- Emf induced is low
- Greater the flux produced
- Longer the delay in establishing a steady current through it
Answer: (d) Longer the delay in establishing a steady current through it
Q4: Which of the following circuit elements will oppose the change in circuit current?
- All of the above
Answer: (b) Inductance
Q5: How does an inductor work?
- Storing energy as a magnetic field.
- A wire piece is charged
- Introducing resistance into a circuit
- Choking off high-frequency ac
Answer:(a) Storing energy as a magnetic field.
Q6: The inductance of the coil is not affected by which of the following?
- The length of the coil
- Number of turns
- The material of the core
- The diameter of the wire
.Answer: (d) The diameter of the wire.
Q7: In a small inductance:
- Large current flow
- Energy is stored and released quickly
- Small current flow
- Energy is stored and released slowly
Answer: (b) Energy is stored and released quickly
Q8: The phenomenon due to which there is an induced current in one coil due to the current in a neighbouring coil is?
- Mutual inductance
- Steady current
Answer: (a) Mutual inductance
Q9: The combination of the same two inductors (33 mH and 55 mH) connected in parallel without mutual inductance will have a value of
- 22 mH
- 88 mH
- 1.8 H
- 21 mH
Answer: (b) 88 mH.
Q10: Three inductance with the values 4 NH, 140 μH, and 5 H are connected in series without mutual inductance. For practical purposes, the net inductance will be very close to
- 4 NH
- 140 μH
- 5 H
- None of these
Answer: (c) 5 H