Question

Three closed similar coils P, Q and R are placed such that their planes are parallel In the coil P and R current of same magnitude flows as shown in the figure Coils Q and R are static while coil P is moved with a uniform speed towards Q then

• A. Clockwise current will be induced in coil Q as seen by eye
• B. Anti-clockwise current will be induced in coil Q as seen by eye
• C. No current will flow in coil P
• D. Current induced in coil Q will be equal to P and R but in opposite direction hence net current in Q will be zero

Answer 1

The correct option is B Anti-clockwise current will be induced in coil Q as seen by eye

Answer is B.

If currents pass along two parallel wires, each wire will set up a magnetic field and the fields will interact. Two parallel coil conductors which each carrying a current in the same direction will attract one another, while two such conductors which carry currents in an opposite direction will repel each other.
Coil P produces a magnetic field which is perpendicular to the current flow in Q. The force acting on Q will be at right angles to the current flow and at right angles to the magnetic field.
Now apply Fleming's left Hand rule: if we point the first finger in the direction of the field, the second finger in the direction of the current, and then our thumb will point in the direction of the direction of the force experienced by the conductor P.
Hence, anti-clockwise current will be induced in coil Q as seen by eye.