# Physics

I need help on this question:

Light bulbs are often assumed to obey Ohm's law. However, this is not really true because their resistance increases substantially as the filament heats up in its "working" state.

A typical flashlight bulb at full brilliance draws a current of approximately 0.5 A when connected to a 3-V voltage source. For this problem, assume that the changing resistance causes the current to be 0.5 A for any voltage between 2 and 3 V.

Suppose this flashlight bulb is attached to a capacitor as shown in the circuit from the problem introduction. If the capacitor has a capacitance of 3 F (an unusually large but not unrealistic value) and is initially charged to 3 V, how long will it take for the voltage across the flashlight bulb to drop to 2 V (where the bulb will be orange and dim)? Call this time tbright.

Express t_bright numerically in seconds to the nearest integer.

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