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. `1.96 xx 10^(-4)T`
B. `1.96xx10^(4)T`
C. `1.96 xx 10^(-5)T `
D. `1.96 xx 10^(5)T`

Answer

C

Explanation

Angle through which magnet is deflected `(theta)= 30^(@)` and horizontal magnetic field `(B_(R))=0.34xx 10^(-4)T` . Magnetic intensity `=B_(R) tan theta = 0.34 xx 10^(-4) xx tan 30^(@) =(0.34 xx 10^(-4)) xx 0.577 =1.96 xx 10^(-5) T `.