Question

A small circular loop of wire is placed inside a long solenoid carrying a current. The plane of the loop contains the axis of the solenoid. If the current in the solenoid is varied, the current induced in the loop is

• A. anticlockwise
• B. clockwise
• C. zero
• D. clockwise or anticlockwise depending on whether the resistance in increased or decreased

Answer 1

The correct option is C zero

Given: Plane of loop contains the axis of solenoid.

Solution: According to the question ,plane of loop is parallel to the axis of the solenoid. So, area vector of loop is perpendicular to magnetic field of solenoid.

$\varphi =(\overrightarrow{B}\times \overrightarrow{A})=BAcos\theta =BA\times 0$

$\varphi =0$

And as we know that $\phi =MI$

So , M=0 and we know that current can be induced here due to mutual induction.

Then current induced in the loop will also be zero

Hence the correct option is C.