Determine thte valur of time constan for the given circuit

Options

A. `(L)/(R_(1)+r+R_(2))`
B. `(L)/((R_(1)+r)`
C. `(L(R_(1)+R_(2)+r))/((R_(1)+r)R_(2))`
D. none of these

Answer

C

Explanation

Here , `R_(eq) =(R_(1)+R_(2))/(R_(1)+r+ R_(2))thereforetau=(L)/(R)= (L(R_(1)+R_(2)+r))/((R_(1)+r)R_(2))`