Question 62: Electromagnetic Induction

Question

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 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:

Accepted Answer

Let's analyze each statement:
$$	extbf{A. The self-inductance of the coil depends on its geometry.}$$
This is true because the self-inductance of a coil is given by formulas that include its geometrical parameters (number of turns, cross-sectional area, length, etc.). For example, for a solenoid,
$$ L = \mu_0 \mu_r \frac{N^2 A}{l}, $$
where $$N$$ is the number of turns, $$A$$ is the cross-sectional area, and $$l$$ is the length.
$$	extbf{B. Self-inductance does not depend on the permeability of the medium.}$$
This is false. The permeability of the medium (represented by $$\mu = \mu_0 \mu_r$$) directly influences the inductance, as seen in the formula above. So, any change in the mediumÃ¢ÂÂs permeability will affect the inductance.
$$	extbf{C. Self-induced e.m.f. opposes any change in the current in a circuit.}$$
This is true, and it is a direct consequence of Lenz's law. The induced electromotive force (e.m.f.) always acts in a direction such that it opposes the change in current that produced it.
$$	extbf{D. Self-inductance is the electromagnetic analogue of mass in mechanics.}$$
This is true. Just as mass resists changes in velocity (inertia), inductance resists changes in current, which is why it is often compared to the inertial mass in mechanical systems.
$$	extbf{E. Work needs to be done against self-induced e.m.f. in establishing the current.}$$
This is true because, when you try to change the current, you must do work to overcome the opposing self-induced e.m.f., storing energy in the magnetic field of the inductor.
Based on the above reasoning, the true statements are A, C, D, and E.
Thus, the correct answer is:
Option C
A, C, D, E only

Answer

A, B, C, E only

Answer

A, B, C, D only

Answer

A, C, D, E only

Answer

B, C, D, E only

Electromagnetic Induction

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