By what factor is the self-inductance of an air solenoid changed if only its number of coil turns,N,is tripled?
A)1/3
B)3
C)6
D)9

Question

Quizplus · Accepted Answer

The self-inductance of a solenoid is directly proportional to the square of the number of coil turns. Therefore, if the number of coil turns is tripled (N becomes 3N), the self-inductance will increase by a factor of (3N/N)^2 = 9. Therefore, the answer is D.

By What Factor Is the Self-Inductance of an Air Solenoid