Why does switching this circuit on take longer

[Pochen Liu]

Homework Statement

In this circuit, switching on is about twice as long as the delay for switching off

2. Homework Equations
3. The Attempt at a Solution
When switching this circuit on the inductor will oppose the change of current therefore basically slow down the lighting of bulb B.

When switching off it opposes the change in current so bulb B will remain lighter for a little bit however why does the time constant change from L/R to L/2R?

 

[Delta2]

Because when you switch off the voltage source is removed, and what do you get if you apply Kirchoff's Voltage Law in the closed loop that contains bulb A, bulb B and the inductor? Notice that the same current runs everywhere now through both bulbs and the inductor.
During switching on, there is the voltage source in the circuit which makes the current through bulb A different than the current through bulb B. That's the key difference between the two cases. if you apply KVL for the same loop during the switching on case, you get different equation.