A copper disc of radius ${\rm{0}}{\rm{.1 m}}$ is rotated about its centre with ${\rm{20}}\,\,{\rm{rev}} - {{\rm{s}}^{ - 1}}$ in a uniform magnetic field of ${\rm{0}}{\rm{.1 T}}$ with its plane perpendicular to the field. The emf induced across the radius of the disc is

$\frac{{\rm{\pi }}}{{20}}{\rm{V}}$

$\frac{{\rm{\pi }}}{{10}}{\rm{V}}$

NEET UG PHYSICS MCQ: ELECTRO MAGNETIC INDUCTION

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A copper disc of radius

\mathrm{0}\mathrm{.1 m}

is rotated about its centre with

\mathrm{20}\,\,\mathrm{rev} - {\mathrm{s}^{ - 1}}

in a uniform magnetic field of

\mathrm{0}\mathrm{.1 T}

with its plane perpendicular to the field. The emf induced across the radius of the disc is

View answer and explanation

Correct option: C

20\,\pi \,\mathrm{mV}

Option C (

20\,\pi \,{\mathrm{mV}}

) is correct because it's the induced emf calculated using the formula for a rotating disc in a magnetic field.

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