Question

The number of turns in the coil of an a.c. generator is $5000$ and the area of the coil is $0.25{\text{m}}^2$. The coil is rotated at the rate of $100\text{cycle per second}$ in a magnetic field of $0.2\text{T}.$ The peak value of the emf generated is nearly

• A. $157\text{kV}$
• B. $220\text{kV}$
• C. $440\text{kV}$
• D. $786\text{kV}$

Answer 1

The correct option is A $157\text{kV}$

Peak value of emf generated by a.c. generator is,

$\epsilon =BAN\omega =BAN\left(2\pi f\right)$

$\epsilon =0.2\times 0.25\times 5000\times 2\times 3.14\times 100$

$\epsilon =157\times {10}^3\text{V}\text{(or)}$

$\epsilon =157\text{kV}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(A\right)$ is the correct answer.