Birds resting on high-voltage power lines are a common sight. A certain copper power line carries a current of 85.8 A, and its resistance per unit length is 14.4 × 10−5 Ω/m. If a bird is standing on this line with its feet 15 cm apart, what is the potential difference across the bird’s feet? Answer in units of V.

1.853×10⁻³ V

Explanation:

Potential Difference: This can be defined as the work done when one coulombs of charge moves from one point to another in an electric Field. The S.I unit is volt (V)

From Ohm's Law,

V = IR Equation 1

Where V = Voltage, I = Current, R = Resistance.

From the question,

R = R'd Equation 2

Where R' = Resistance per length, d = distance

Substitute equation 2 into equation 1

V = IR'd Equation 3

Given: I = 85.8 A, R' = 14.4×10⁻⁵ Ω/m, d = 15 cm = 0.15 m

Substitute into equation 3

V = 85.8×14.4×10⁻⁵×0.15

V = 1.853×10⁻³ V.

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