A coil has 1,000 turns and 500 cm2 as its area. The plane of the coil is placed at right angles to a magnetic induction field of 2 ×10–5wb/m2. The coil is rotated through 1800 in 0.2 seconds. The average e.m.f induced in the coil, in milli-volts.

Given data:

No of turns n=1000

Area $A = 500 {cm}^{2}$

Magnetic field $B = 2 \times 10^{- 5} \frac{wb}{m^{2}}$

Coil rotated through 180⁰

Time t=0.2 s

Concept used: Induced EMF

Detailed solution:

Initial flux $ϕ_{1} = N B A \cos 0 ° = N B A$

When the coil is turned through $180 °$ , the flux will be,

$ϕ_{2} = N B A \cos (180 °) = - N B A$

Net flux will be $Δ ϕ = ϕ_{2} - ϕ_{1} = - 2$ NBA

The magnitude of induced EMF is,

$E = |\frac{Δϕ}{Δt}| = \frac{2 NBA}{Δt}$

$E = \frac{2 \times 1000 \times 2 \times 10^{- 5} \times 500 \times 10^{- 4}}{0.2}$

$E = 10^{- 2} V$

$E = 10 m V$ .

A coil has 1,000 turns and 500 cm² as its area. The plane of the coil is placed at right angles to a magnetic induction field of 2 ×10^–5wb/m². The coil is rotated through 180⁰ in 0.2 seconds. The average e.m.f induced in the coil, in milli-volts.