A coil having 'n' turns and resistance `R Omgea` is connected with a galvanometer of resistance `4R Omega`. This combination is moved in time 't' seconds from a magnetic flux `phi_(1)`. Weber to `phi_(2)` Weber. The induced current in the circuit is

Options

A. `-(phi_(2)-phi_(1))/(5Rnt)`
B. `-(n(phi_(2)-phi_(1)))/(5Rt)`
C. `-((phi_(2)-phi_(1)))/(Rnt)`
D. `-(n(phi_(2)-phi_(1)))/(Rt)`

Answer

B

Explanation

The change in flux `= n(phi_(2)-phi_(1))`
Total resistance of the circuit `= 4R+R=5R`
Thus induced current, `i=(Delta phi//Delta t)/(R )=(n(phi_(2)-phi_(1)))/(5RT)`.