Question

A long solenoid carrying current 'I₁' produces magnetic field 'B₁' along its axis. If the current is reduced to 25% and number of turns per cm are increased four times, then new magnetic field 'B₂' is ____________.

विकल्प

• B₁

• 16B₁

• `"B"_1/4`

• 4B₁

Answer 1

A long solenoid carrying current 'I₁' produces magnetic field 'B₁' along its axis. If the current is reduced to 25% and number of turns per cm are increased four times, then new magnetic field 'B₂' is B₁.

Explanation:

`"B"_1 = mu_0  "I"_1 "n"`

`"B"_2 = (4"n") "I"_1/4 mu_0 = "B"_1`