A coil of mean area 500 cm 2 and having 1000 turns is held perpendicular to a uniform field of 0.4 gauss. the coil is turned through 180° in 1 / 10 second. The average induced emf (in V ) is.

Question

A coil of mean area 500 cm 2 and having 1000 turns is held perpendicular to a uniform field of 0.4 gauss. the coil is turned through 180° in 1 / 10 second. The average induced emf (in V ) is. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

When the plane of coil is perpendicular to field, the angle between area

A

and field

B

is

0^{\circ}

.
The flux linked with coil

ϕ_{1} = NB A cos 0 = NB A

.
When coil is turned through

18 0^{\circ}

, the flux linked

ϕ_{2} = NB A cos π = - NB A

∴

Change in flux

ϕ = ϕ_{2} - ϕ_{1} = - 2 NB A

The magnitude of the induced emf is

ε = - \frac{d ϕ}{d t} = \frac{2 NB A}{d t}

= \frac{2 \times 1000 \times 0.4 \times 1 0 ^{- 4} \times 500 \times 1 0 ^{- 4}}{0.1}

= 0.04 V

Q. A coil of mean area 500cm2 and having 1000 turns is held perpendicular to a uniform field of 0.4 gauss. the coil is turned through 180∘ in 1/10 second. The average induced emf (in V ) is_____.

Q. A coil of mean area $500 c m^{2}$ and having $1000$ turns is held perpendicular to a uniform field of $0.4$ gauss. the coil is turned through $18 0^{\circ}$ in $1/10$ second. The average induced emf (in $V$ ) is_____.