Question

Calculate the resistance of 1 metre of copper wire that has a cross sectional area of about 2*10^-2 cm^2. Compare the value of this resistance with that of a flashlight bulb which has a power rating of 1W and operates at 3V. What does this comparison tell you?

Answer 1

Dear Student,

◆ Answer with Explaination -

Resistance of copper wire is -

Rw = ρl / A

Rw = 1.68×10^-8 × 1 / 2×10^-6

Rw = 8.4×10^-3 ohm

Resistance of electric bulb will be -

Rb = V^2 / P

Rb = 3^2 / 1

Rb = 9 ohm

From this, resistance of wire is less than that of electric bulb.

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