Correct Answer - A
Only half area of ring area of ring will be considered.
`therefore phi_(B)=BS=B.(pir^(2))/(2)`
`thereforee=(dphi_(B))/(dt)=(pir^(2))/(2).(dB)/(dt)=(pi(0.1)^(2))/(2)xx0.01=(pi)/(2)xx10^(-4)V`
`thereforei=(e)/(R)=((pi)/(2)xx10^(-4))/(4)=(pi)/(8)xx10^(-4)=3.9xx10^(-5)A`