The magnetic needle of a tangent galvanometer is deflected at an angle `30^(@)` due to a magnet. The hoeizontal component of earth's magnetic field `0.34xx10^(-4)T` is along the plane of the coil. The magnetic intensity is

Options

A. `1.96xx10^(-4)T`
B. `1.96xx10^(4)T`
C. `1.96xx10^(-5)T`
D. `1.96xx10^(5)T`

Answer

C

Explanation

In a tangent galvanometer,
applying tangent law
`B=H tan theta`
`B=H tan theta`
`B=0.34xx10^(-4) tan 30^(@)`
`B=0.34xx10^(-4)xx1/(sqrt(3))`
`B=1.96xx10^(-5)T`