Question

The r.m.s. value of induced voltage in a coil of 25 turns each of area 30 sq. cm. rotating at 2000 r.p.m. about an axis at right angles to magnetic field is (B = 5 x 10^-4 Wb/m²) ____________.

Options

• 555 mV

• 55.5 mV

• 5.55 mV

• 55 mV

Answer 1

The r.m.s. value of induced voltage in a coil of 25 turns each of area 30 sq. cm. rotating at 2000 r.p.m. about an axis at right angles to magnetic field is 5.55 mV.

Explanation:

`"e"_"rms" = "e"_0/sqrt2 = (2pi "fnAB")/sqrt2 = sqrt2 pi "fnAB"`

`= sqrt2 xx pi xx (2000/60) xx 25 xx (30 xx 10^-4) xx 5 xx 10^-4`

`approx 5.55  "mV"`