An indcutor having self inductance L with its coil resistance R is connected across a battery of emf `elipson`. When the circuit is in steady state t = 0, an iron rod is inserted into the inductor due to which its inductance becomes nL (ngt1).

When again circuit is in steady state, the current in it is

Options

A. `I lt epsilon//R`
B. `I gt epsilon//R`
C. `I = epsilon//R`
D. None of these

Answer

C

Explanation

When inductance of coil is changed abruptly, flux it remains same. i.e. `phi=LI=constant`. Since here incuctance will increase on insertion of iron rod, so current will decrease. Now current will increases to attain the steady state value `(E//R)`. During thsi time, inductance (nL) will remain same and p.d. across A and B will also remain same. But as current will change with time so rate of prodution of heat will vary.