JEE Main 2021 Physics question

Magnetic fields at two points on the axis of a circular coil at a distance of 0.05 m and 0.2 m from the centre are in the ratio 8 : 1. The radius of the coil is .

• (A)0.2 m
• (B)0.1 mCorrect
• (C)0.15 m
• (D)1.0 m