Question

If both the number of turns and core length of an inductor is doubled, keeping other factors constant, then its self-inductance will be

A. Halved
B. Doubled
C. Quadrupled
D. Remains the same

Answer 1

When both the number of turns and the core length of an inductor are doubled, the self-inductance of the inductor will be doubled because of the squared relationship with the number of turns.

Step-by-step explanation:

The self-inductance of an inductor is determined by several factors, including the number of turns in the coil (N) and the core length (L). According to the formula for an inductor's self-inductance ∐, which can be represented as ∐ ≈ N² × (∐ Core/Length), if both the number of turns and the core length are doubled, the self-inductance will be affected as follows:

1. Doubling the number of turns (N) would increase the self-inductance by a factor of 4 (∐ becomes 4N²).
2. Doubling the core length (L) at the same time would then decrease the self-inductance by a factor of 2 (∐ becomes 2N²), as it is inversely proportional to the length.

Therefore, the new self-inductance would be 4N²/2 = 2N². This means that the self-inductance would be doubled, hence the correct answer is B. Doubled.