Regarding self-inductance:
A. The self-inductance of the coil depends on its geometry.
B. Self-inductance does not depend on the permeability of the medium.
C. Self-induced e.m.f. opposes any change in the current in a circuit.
D. Self-inductance is the electromagnetic analogue of mass in mechanics.
E. Work needs to be done against self-induced e.m.f. in establishing the current.
Choose the correct answer from the options given below:
Answer: (C) A, C, D, E only
For a solenoid $L = \mu n^2Al$.
- A: $L$ depends on the number of turns, area and length: correct.
- B: $L$ is proportional to the permeability $\mu$ of the core: wrong.
- C: By Lenz's law the self-induced emf opposes the change of current: correct.
- D: Inductance resists changes in current just as mass resists changes in velocity ($\tfrac{1}{2}LI^2$ vs $\tfrac{1}{2}mv^2$): correct.
- E: Energy $\tfrac{1}{2}LI^2$ must be supplied against the back emf while the current builds up: correct.
A, C, D, E only.
Solution by Sreeraj P, M.Sc Physics