An emf is generated by an ac generator having 100 turn coil, of loop area 1 m². The coil rotates at a speed of one revolution per second and placed in a uniform magnetic field of 0.05 T perpendicular to the axis of rotation of the coil. The maximum value of emf is :-

When a coil rotates in a magnetic field of strength ‘B‘ then EMF induced in the loop,
$\mathrm{e}=\mathrm{nAB\omega sin}\mathrm{\omega t}$
where
n = no. of turns in the coil
A = area of the coil
B = magnetic field strength
$\omega$ = angular velocity
here, $\mathrm{n}=100,\mathrm{A}=1{\mathrm{m}}^2,\mathrm{\omega }=1\mathrm{rps}=2\mathrm{\pi rad}/\mathrm{s}$
B = 0.05 T
maximum emf = e =nAB$\omega$
$=100\times 1\times 0.05\times 2\mathrm{\pi }=10\mathrm{\pi }=31.4$ volts.