Question

Question 4.22: The wires which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart? Is the force attractive or repulsive?

Class 12 - Physics - Moving Charges And Magnetism Moving Charges And Magnetism Page-171

Answer 1

Given:
Current through the wire, I = 300 A
Length of wire, L1 = 70 cm
Length of wire, L2 = 70 cm
Distance between the wires, d = 1.5 cm

force can be determined by $\bf{F=\frac{\mu_0I^2}{2\pi d}}$

Here, $\mu_0$ = 4π × 10^-7 , I = 300A
d = 1.5 cm = 1.5 × 10^-2 m = 0.015 m
now, F = (4π × 10^-7 × 300²)/(2π × 0.015)
F = (2 × 90000 × 10^-7)/(0.015)
F = 1.2 N/m

Answer 2

Answer:

here is the answer to your question.

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