Question 202: Magnetism and Matter

Question

A circular coil having N turns and radius r
carries a current I. It is held in the XZ plane in
a magnetic field B$${\mathop i\limits^ \wedge  }$$ . The torque on the coil due
to the magnetic field is :

Accepted Answer

According to the question, the situation can be drawn as
Let the current I is flowing in anti-clockwise direction, then the magnetic moment of the coil is
m = NIA
where, N = number of turns in coil
and A = area of each coil = $$\pi$$r
2
.
Its direction is perpendicular to the area of coil and is along Y-axis.
Then, torque on the current coil is
$$	au  = m 	imes B = mB\sin 90^\circ  = NIAB$$
$$ = NI\pi {r^2}B(N - m)$$

Answer

$${{B{r^2}I} \over {\pi N}}$$

Answer

B$$\pi $$r2IN

Answer

Zero

Answer

$${{B\pi{r^2}I} \over { N}}$$

Magnetism and Matter

A circular coil having N turns and radius r carries a current I. It is held in the XZ plane in a magnetic field B${\mathop i\limits^ \wedge }$ . The torque on the coil due to the magnetic field is :

Choose the correct answer: