Question

Birds resting on high-voltage power lines are a common sight. The copper wire on which a bird stands is 2.3 cm in diameter and carries a current of 45 A. If the bird's feet are 3.9 cm apart, calculate the potential difference between its feet. (The resistivity of the wire is 1.7 10-8 Ω · m)

Answer 1

Step-by-step explanation:

It is given that,

Diameter of the copper wire, d = 2.3 cm

Radius of copper wire, r = 1.15 cm = 0.0115 m

Distance between bird's feet, l = 3.9 cm = 0.039 m

The resistivity of the wire,
`\rho=1.7* 10^(-8)\ \Omega-m`

We need to find the potential difference between bird's feet. The resistance of the wire is calculated by :

`R=\rho* (l)/(A)`

`R=1.7* 10^(-8)\ \Omega-m* (0.039\ m)/(\pi(0.0115\ m)^2)`

R = 0.00000159 ohms

`R=1.59* 10^(-6)\ \Omega`

Let V is the potential difference between bird's feet. It can be calculated using Ohm's law as :

`V=I* R`

`V=45\ A* 1.59* 10^(-6)\ \Omega`

V = 0.000071 volts

or

`V=7.1* 10^(-5)\ volts`

So, the potential difference between the bird's feet is
`7.1* 10^(-5)\ volts`. Hence, this is the required solution.