Question

A coil has an area of 0.05m2 and has 800 turns.After placing the coil in a magnetic field of strength 4*10^-5​​ Wbm^-2,perpendicular to the field, the coil is rotated by 90% in 0.1 s. The value of average emf induced is

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{number}\mathrm{of}\mathrm{turns},\mathrm{n}=800 \\ \mathrm{magnetic}\mathrm{field},\mathrm{B}=4\times {10}^{-5}\mathrm{Wb}/{\mathrm{m}}^2 \\ \mathrm{area},\mathrm{A}=0.05{\mathrm{m}}^2 \\ \mathrm{Initial}\mathrm{flux}=\mathrm{nBA} \\ \mathrm{On}\mathrm{rotating}\mathrm{the}\mathrm{coil}\mathrm{by}90°,\mathrm{flux}\mathrm{becomes}\mathrm{zero}. \\ \mathrm{Therefore},\mathrm{e}=\frac{\mathrm{d\varphi }}{\mathrm{dt}} \\ \mathrm{e}=\frac{\mathrm{nBA}}{\mathrm{dt}} \\ \mathrm{e}=\frac{800\times 4\times {10}^{-5}\times 0.05}{0.1}=0.016\mathrm{V} \end{gathered}$$