Physics

Problem

The electric current in a circular coil of 2 turns produces a magnetic induction

B_1

at its centre. The coil is unwound and is rewound into a circular coil of 5 turns and the same current produces a magnetic induction

B_2

at its centre. The ratio of

\frac{B_2}{B_1}

is : (A)

\frac{5}{2}

(B)

\frac{25}{4}

(C)

\frac{5}{4}

(D)

\frac{25}{2}