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 other quantities remained the same, the magnetic field inside the solenoid would remain the same. become twice as strong. become one half as strong.

Answer 1

Step-by-step explanation:

length of solenoid, L

current, I

number of turns, N

The magnetic field due to a solenoid is

`B=(\mu _(0)NI)/(L)` .... (1)

Now the length is 2L

The new magnetic field is

`B'=(\mu _(0)NI)/(2L)` ..... (2)

So, B' = B /2

Thus, the magnetic field becomes half.