What will be the emf induced in a square shaped coil of side 0.2 m having 200 turns, placed perpendicular to a magnetic field which is increasing at the rate of \( 0.5\,\mathrm{T\,s^{-1}} \)?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( 4.0\,\mathrm{V} \)
By Faraday's law the emf in a coil of \( N \) turns is \( \varepsilon = N\,d\Phi/dt \). The coil is perpendicular to the field, so \( \Phi = BA \) and, with the area fixed, only \( B \) changes.
\( \displaystyle A = (0.2)^{2} = 0.04\,\mathrm{m^2} \)
\( \displaystyle \varepsilon = N\,A\,\frac{dB}{dt} = 200 \times 0.04 \times 0.5 = 4.0\,\mathrm{V} \)