Question

An elastic circular wire of length $\ell$ carries a current $I_0$. It is placed in a uniform magnetic field $\overrightarrow{B}$ (out of paper) such that its plane is perpendicular to the direction of $\overrightarrow{B}$. The wire will experience:

• A. No force
• B. A stretching force
• C. A compressive force
• D. A touque

Answer 1

The correct option is A No force

Given that,

Length of wire $=l$

Current $=I$

We know that,

The plane is perpendicular of the direction of magnetic field

So, the angle between normal plane and magnetic field is ${90}^0$

So, the force is

$F=BIl\sin \theta$

$F=B\times l\times I\sin {90}^0$

$F=0$

Hence, the wire will experience no force