Question

If the direction of the current changes in the current carrying loop placed in some magnetic field perpendicular to loop, then Potential energy of loop is not effected because current is a scalar quantity.Enter 1 if true and 0 if False.

Answer 1

For the current loop ABCD in magnetic field $\overrightarrow{B}$

Let current flowing = I

Area enclosed = A and

$\mu$ = magnetic dipole moment.

Now torque expression

$\tau =\mu \times B_{\text{ext}}$

$\tau =\mu B_{\text{ext}}\sin \theta$

Thus potential energy,

$U=\int \tau d\theta$

$=\int \mu B\sin \theta d\theta$

$U=\mu B\cos \theta$

Thus U depends of $\mu$.

Here U depends on $\mu$, magnetic moment which depends on direction of current.

Thus potential energy changes.

Hence false(0).