A tangent galvanometer shown a deflection of `45^@` when `10 mA` of current is passed through it. If the horizontal component of the earth's magnetic field is `B_H = 3.6 xx 10^(-5) T` and radius of the coil is `10cm`, find the number of turns in the coil.

Options

A. `5700 turns`
B. `57 turns`
C. `570 turns`
D. `5.7turns`

Answer

C

Explanation

`K=(2piB_(H))/(mu_(0)n)`
or `n=(2rB_(H))/(mu_(0)K)=(2xx0.1xx3.6xx10^(-5))/(4pixx10^(-7)xx10xx10^(-3))`
`=(1.8xx10^(3))/3.14=570`