In a magnetic field of `0.05T`, area of a coil changes from `101 cm^(2)` to `100 cm^(2)` without changing the resistance which is `2Omega`. The amount of charge that flow during this period is

Options

A. `2.5 xx 10^(-6)`C
B. ` 2xx 10^(-6)` C
C. `10^(-6)` C
D. `8 xx 10^(-8)` C

Answer

A

Explanation

(i)
`{:("Magnetic flux",phi=B*A),("Change in flux", dphi=B*dA):}`
`=0.05(101-100)10^-4=5xx10^-4Wb`
`:.` Charge
`dq=(dphi)/R=(5xx10^-6)/2=2.5xx10^-6C`