Khimraj
Last Activity: 6 Years ago
As the disc rotates, any of its radii cuts the lines of force of magnetic field.
Area swept by radius vector during one revolution
= πr2
= π(10 cm)2
= 100π cm2
= π×10-2 m2
Area swept in one second,
A = (area swept in one revolution) × (Number of revolutions )
= π×10-2×1000
A = 600 πm2
Rate of change of magnetic flux
= dϕB/dt
= BA
= 0.2×600π
= 120π Wb
According to Faraday’s law, magnitude of induced e.m.f is,
E = dϕB/dt
Therefore, magnitude of e.m.f. is
E = 120 πV