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)/(5 RnT)`
B. `-(n ( phi _2 - phi _1))/(5Rt)`
C. `-((phi_2-phi_1))/(Rnt)`
D. `-(n(phi_2 - phi _1))/( Rt)`

Answer

B

Explanation

Given
number of turns in coil = n
we have that ,
Current (i) ` = (e ) /(R') = (- Delta phi )/(R 'Delta t) " " [ :' e = (- Delta phi)/(delta t)]`
` R'= R+ 4R`
` i=- ((phi _2 - phi _1))/((R+4R)Delta t)`
` i= ((phi_2 - phi _1))/(5 R ( Delta t))`
Here , coil have n number of turns
Hence , `i= ( n( phi_2 - phi _1))/( 5R (Delta t))`
Induced current `i = -(n(phi_2- phi _1))/(5Rt)`