A circular coil of radius 10 cm, 500 turns and resistance 2 Omega is placed with its plane prependicular to the horizontal component of the earth's magnetic field. It is rotated about its vertical diameter through `180^(@)` in 0.25 s. Estimate the magnitude of the e.m.f and current induced in the coil. Horizotal component of earth's magnetic field at the place is `3 xx 10^(-5) T`.

Options

A. 6 V, plance of the coil normal to magnetic meridian
B. 2 V, plance of the coil normal to magnetic meridian
C. 6 V, plance of the coil normal to magnetic meridian
D. 2 V, plance of the coil normal to magnetic meridian

Answer

A

Explanation

Magnetic field of 1 A turn/,
`=4pixx10^(-7)T`
Field at center `B=(mu_(0)Nl)/(2r)=(mu_(0)N)/(2r)xxV/R`
`or V=(2rRB)/(mu_(0)N)`
`2xx(5xx10^(-2))xx10`
`thereforeB=(xx(30xx4pixx10^(-7)))/((4pixx10^(-7))xx5)`
`or V=6V`
To unlify the horizonhtal component of magnetic field of earth, plane of the coil should be normal to magnetic meridian.