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1. The circuit at right contains a battery, a bulb, a switch, and a capacitor. T

ID: 1790414 • Letter: 1

Question

1. The circuit at right contains a battery, a bulb, a switch, and a capacitor. The capacitor is initally uncharged. a. Desa ibe the behavior of the bulb in the two Bulb A situations below Batery Capaciior The switch is first moved to position I Describe the behavior of the bulb from just after the switch is closed until a long time later Explain. i. ii- The switch is now moved to position 2, Describe the behavior ofthe bulbfron just afer he switch is closed until a long time laer. Explain your reasoning. b. A second identical bulb is now added to the circuit as shown. The capacitor is discharged Bulb B i. The switch is now moved to position Bulb C Describe the beha vior of bulbs B and C from just after the switch is closed until a long time later. Explain. Batterv How does the initial brightness of bulb C compare to the initial brightness of bulb A in question i of part a? Explain your reasoning. A long time after the switch is closed, is the potential difference across the capacitor greater than, less than, or equal to the potential difference across the battery? Explain.

Explanation / Answer

a)i) This is case of charging of a capacitor. The bulb glows brightly just after switch is closed, but it gets dimmer with time and after a long time it stops glowing as current decays with time.

ii)This is a case of discharging of capacitor. The bulb glows brightly just after switch is closed, but it gets dimmer with time and after a long time it stops glowing as current decays with time.

b) i) This is case of charging of a capacitor. The bulbs glow brightly just after switch is closed, but they get dimmer with time and after a long time they stop glowing as current decays with time.

Initial brightness of Bulbs C is less than A initially because current is less in C as resistance is more in this circuit. potential difference across capacitor is equal to that across battery.

ii) This is case of discharging of a capacitor. The bulbs glow brightly just after switch is closed, but they get dimmer with time and after a long time they stop glowing as current decays with time.

Initial brightness of Bulbs C is less than A initially because current is less in C as resistance is more in this circuit.

potential difference across capacitor is less than that across battery as voltage across capacitor decreases to zero.