1. The length of a 60 W, 240 light bulb filament is 60 cm. Part A: If the potent

Question

1. The length of a 60 W, 240 light bulb filament is 60 cm.

Part A: If the potential difference across the filament is 120 V, what is the strength of the electric field inside the filament?

Express your answer using two significant figures.

Part B: Suppose the length of the bulb's filament were doubled without changing its diameter or the potential difference across it. What would the electric field strength be in this case?

Express your answer using two significant figures.

Part C: Remembering that the current in the filament is proportional to the electric field, what is the current in the filament following the doubling of its length?

Express your answer using two significant figures.

Part D: What is the resistance of the filament following the doubling of its length?

Express your answer using two significant figures.

Explanation / Answer

1) E = V/L = 120/0.6 = 200 N/C

2) IF LENGTH DOUBLED THEN ELECTRIC FIELD IS DECREASED BY 2 TIMES THAT IS 100 N/C

3) I^2R = P
I^2*240 =60
I = 0.5 A
When length is doubled the resistance will be doubled and = 480 ohm

Assuming the power remains the same

I^2 480 = 60
I = 0.35 A
R =2*240 = 480 ohm.

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