A coil formed by wrapping 50 turns of wire in the shape of a square is positioned in a magnetic field so that the normal to the plane of the coil makes an angle of `30^@`. with the direction of the field. When the magnetic field is increased uniformly from `200 muT` to `600muT` in `0.4 s`, an emf of magnitude 80.0 mV is induced in the coil. What is the total length of the wire?

Answer

B

Explanation

`e=(N/_\phi)/(/_\t)=((NS/_\B)/(/_\t))cos30^@`
`:. S=((e/_\t)/(N/_\B))sec30^@`
`=[((80xx10^-3)(0.4))/((50)(400x10^-6))][2/sqrt3]=1.85m`
`:.` Side of square `=1.36m`
Total length of wire `=50(4xx1.36)`
`=272m`