AIPMT PRELIMS2003Physics-Magnetism

AIPMT PRELIMS 2003 Physics Magnetic Field in Solenoids MCQ Question

Type: MCQ-conceptual-Medium-Class 12

A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is -

A

B/2

B

B

C

2B

D

4B

Correct Answer

Option B

Detailed Explanation

The magnetic field inside a solenoid is given by B=μ0nIB = \mu_0 n I. If the current is doubled and the number of turns per cm is halved, the product nInI remains the same, so the magnetic field remains unchanged.

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