Question

A student gets confused if two parallel wires carrying current in same direction attract or repel. Which rules will he need to reach at the right conclusion?

• A. Right Hand Thumb Rule
• B. Fleming's Left Hand Rule
• C. Both A and B
• D. None

Answer 1

Answer: (C)

Both A and B

Consider two parallel wires carrying current in the same direction.

First, apply Right Hand Thumb Rule on any one wire to find direction of magnetic field at the second wire.

Next, apply Fleming's Left hand rule on the second wire to find force applied on the second wire.

It is observed that force is in direction of the first wire, i.e. second wire is attracted to first wire.

Similarly, repeating above steps for first wire, it is observed that first wire is also attracted to second wire.

Hence, they attract.