Answer the following:
(a)Define SI unit of current in terms of the force between two parallel current carrying conductors.
(b) Two long straight parallel conductors carrying steady currents `I_(a)andI_(b)` along the same direction are separated by a distance d. How does one explain the force of attraction between them? If a third conductor carrying a current `I_(c)` in the opposite direction is placed just in the middle of these conductors , find the resultant force acting on the third conductor.

Explanation

### Solution:

#### (a) Definition of SI Unit of Current

The SI unit of electric current is the **Ampere (A)**. It can be defined in terms of the force between two parallel current-carrying conductors as follows:

When two long, straight, parallel conductors carrying steady currents \( I_A \) and \( I_B \) are placed one meter apart in a vacuum, they exert a force on each other. The force per unit length \( F/L \) between these two conductors is given by the formula:

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