The self inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as

Options

A. l and increase
B. l decreases and A increases
C. A increases and A decreases
D. both l and A decrease

Answer

B

Explanation

The self-induction L of a solenoid of length l and area of cross section A with fixed number of turns is
`L = (mu_(0) N^(2) A)/(l)`
Obviously, L increases when l decreases and A increases. Choice (b) is correct.