Question

Consider a solenoid of length L, N windings, and radius b (L is much longer than b A current I). is flowing through the wire. If the length of the solenoid became twice as long (2L), and all other quantities remained the same, the magnetic field inside the solenoid would _________.

Answer 1

The magnetic field inside the solenoid would decrease by a factor of 2.

Step-by-step explanation:

The magnetic field, B, of a solenoid of length L, N windings, and radius b with a current, I, flowing through it is given as:

B = (N * r * I) / L

If the length of the solenoid is doubled, 2L,the magnetic field becomes:

B2 = (N * r * I) / 2L

B2 = ½ B

The magnetic field will decrease by a factor of 2.