A coil having n turns and resistance `R Omega` is connected with a galvanometer of resistance `4R Omega`. This combination is moved in time t seconds from a magnetic field `W_(1)` weber to `W_(2)` weber. The induced current in the circuit is

Options

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

Answer

B

Explanation

(b) (delta phi)/(deltat)=(W_(2)-W+(1))/(t)`
`R_(tot)=(R+4R)(Omega)=5R(Omega)`
`i=(nd phi)/(R_(tot)dt)=(-n(W_(2)-W_(1)))/(5Rt)`
`(:. W_(2) & E_(1) are magnetc flux)`.