Magnetic Effects Of Current Question 225

Question: Two long conductors, separated by a distance d carry current I1 and I2 in the same direction. They exert a force F on each other. Now the current in one of them is increased to two times and its directions is reversed. The distance is also increased to 3d. The new value of the force between them is [AIEEE 2004]

Options:

A) ? 2F

B) F/3

C) 2F/3

D) ? F/3

Show Answer

Answer:

Correct Answer: C

Solution:

$ F\propto \frac{i_{1}i_{2}}{a} $ ; Since one of the current increase two times and distance increases three times, so force become $ \frac{2}{3} $ times. Also due to the reversal of direction of current force becomes negative.