A coil having n trurns and resistance ` R Omega ` 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 circult 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

Answer(2) Induced current, `I = in/R = (N Delta phi/ R Deltat)`
` R_equ = 4R + R = 5R`
`Delta phi = (phi_1 - phi_2)`
` Rightarrow I = (n[phi_1 - phi_2]/ 5Rt)`
`therefore I = (-n(phi_2 - phi_1)/5Rt)`