\(i=\frac{E}{R_2}\left[1-e^{-R_2 t / L}\right]\)
\(\Rightarrow \frac{d i}{d t}=\frac{E}{R_2} \cdot \frac{R_2}{L} \cdot e^{-R_2 t / L}=\frac{E}{L} e^{-\frac{R_2 t}{L}}\)
Hence, potential drop across
\(L =\left(\frac{E}{L} e^{-R_2 t / L}\right) L=12 e ^{-5 t }\,V\)
$\phi=2 t^3+4 t^2+2 t+5 \;W b$
કોઇલમાં $t=5\; s$ પર પ્રેરિત થતું $emf$ $..........\,V$ હશે.