Question 284: Magnetism and Matter

Question

A circular coil having 200 turns, $$2.5 	imes 10^{-4} \mathrm{~m}^2$$ area and carrying $$100 \mu \mathrm{A}$$ current is placed in a uniform magnetic field of $$1 \mathrm{~T}$$. Initially the magnetic dipole moment $$(\vec{M})$$ was directed along $$\vec{B}$$. Amount of work, required to rotate the coil through $$90^{\circ}$$ from its initial orientation such that $$\vec{M}$$ becomes perpendicular to $$\vec{B}$$, is ________ $$\mu$$J.

Accepted Answer

$$\begin{aligned}
& W=U_f-U_i=(-M B \cos 90)-(-M B \cos 0) \
& \Rightarrow W=M B=N i A B=5 \mu \mathrm{J}
\end{aligned}$$

Magnetism and Matter

Integer / Numeric Answer Type