Question

When a wire loop is rotated in a magnetic field, the direction of induced emf changes in every

• A. one revolution
• B. $\frac{1}{2}$ revolution
• C. $\frac{1}{4}$ revolution
• D. 2 revolution

Answer 1

Answer: (B)

$\frac{1}{2}$ revolution

The induced EMF in a wire loop present in a magnetic field is given as a sinusoidal function.

$E=E_{o}sin\left(\omega t\right)$

The sinusoidal function has two sign changes in one cycle. Therefore, in every half of its revolution, the direction of the EMF induced will change.