Question 314: Magnetism and Matter

Question

A coil in the shape of an equilateral triangle of side 10 cm lies in a vertical plane between the pole pieces of permanent magnet producing a horizontal magnetic field 20 mT. The torque acting on the coil when a current of 0.2 A is passed through it and its plane becomes parallel to the magnetic field will be $$\sqrt x $$ $$	imes$$ 10
$$-$$5
Nm. The value of x is .................

Accepted Answer

$$\overrightarrow 	au   = \overrightarrow M  	imes \overrightarrow B  = MB\sin 90^\circ $$
$$ = MB = {{i\sqrt 3 {l^2}} \over 4}B$$
$$ = \sqrt 3  	imes {10^{ - 5}}$$ N $$-$$ m

Magnetism and Matter

Integer / Numeric Answer Type