Introduction:
In this circuit, we have a 600mH inductor and two resistors, one of 4ohm and the other of 2ohm, connected to a 12V cell through a switch. When the switch is closed, the circuit is completed, and current flows through the circuit.

Explanation:

Step 1: Before the switch is closed, the circuit is open, and no current is flowing through it.

Step 2: When the switch is closed, the circuit is completed, and current starts flowing through the circuit.

Step 3: The inductor initially resists the flow of current through it. As a result, the current in the circuit builds up slowly.

Step 4: As the current builds up, the voltage across the inductor increases due to its self-inductance.

Step 5: The voltage across the inductor opposes the flow of current, and the rate of increase of current decreases.

Step 6: Eventually, the current in the circuit reaches a steady state, and the voltage across the inductor becomes zero.

Step 7: At this steady state, the current in the circuit is determined by the total resistance in the circuit.

Step 8: The total resistance in the circuit is the sum of the resistance of the two resistors, which is 6ohm.

Step 9: Using Ohm's law, we can calculate the steady-state current in the circuit as I = V/R, where V is the voltage of the cell, and R is the total resistance of the circuit.

Step 10: Thus, the steady-state current in the circuit is I = 12/6 = 2A.

Step 11: The time constant of the circuit is given by L/R, where L is the inductance of the inductor and R is the total resistance of the circuit.

Step 12: Thus, the time constant of the circuit is 600mH/6ohm = 0.1s.

Step 13: After one time constant, the current in the circuit has reached approximately 63% of its steady-state value.

Step 14: After two time constants, the current in the circuit has reached approximately 86% of its steady-state value.

Step 15: After three time constants, the current in the circuit has reached approximately 95% of its steady-state value.

Step 16: After five time constants, the current in the circuit has reached approximately 99% of its steady-state value.

Conclusion:
In conclusion, when the switch is closed, the circuit is completed, and current starts flowing through the circuit. The inductor initially resists the flow of current through it, which leads to a slow buildup of current. Eventually, the current in the circuit reaches a steady state, determined by the total resistance in the circuit. The time constant of the circuit is given by L/R, where L is the inductance of the inductor and R is the total resistance of