Question

A circular disc of radius $0.2\, m$ is placed in a uniform magnetic field of induction $(\frac{1}{\pi})Wb\,m^{-2}$ in such a way that its axis makes an angle of $60^{\circ}$ with $\vec{B}$. The magnetic flux linked with the disc is

• A. $0.02\, Wb$
• B. $0.06\, Wb$
• C. $0.08\, Wb$
• D. $0.01\, Wb$

Answer 1

Answer: (A)

$0.02\, Wb$

Answer 2

Here, $r =0.2\,m$, $B =\frac{1}{\pi}\,Wb\,m^{-2}$, $\theta=60^{\circ}$ $\therefore$ Magnetic flux, $\phi=BA\, cos\,\theta=B(\pi\,r^{2})cos\, \theta$ $=\frac{1}{\pi} \pi(0.2)^{2} \, cos\, 60^{\circ}$ $=0.02\, Wb$