Let r1 and r2 are the radius of coil 1 \& 2 . If B1 and B2 are magnetic induction at their centre, then B1=
µ0I1
2r1
; and B2=
µ0I2
2r2
Since B1=B2; and r1=2r2 therefore I1=2I2 Again if R1 and R2 are resistance of the coil 1 and 2 then R1=2R2 (as R∝ length =2πr ) and if V1 and V2 are the potential difference across them respectively, then