A battery of E Volts is supplying a steady current to a series circuit of total resistance RΩ and inductance L Henry. A part R1 of the total resistance is suddenly short circuited. Find the expression for current flowing through the battery subsequent to the operation.

• A.  i = {E / R1 - R)}(1- e - (R1 - R) t / L)
• B.  i = {E / R}[1-(R1 / R) *e - {(R - R1 )*t/L}
• C.  i = {E / (R - R1)}[1-(R1 / R) *e- {(R - R1 )t/L}
• D. None of these

Answer: (C)