Two concentric and coplanar circular loops P and Q have their radii in the ratio................

These are the options for the question :Two concentric and coplanar circular loops P and Q have their radii in the ratio 2:3. Loop Q carries a current 9 A in the anticlockwise direction. For the magnetic field to be zero at the common centre, loop P must carry

(i) 3A in clockwise direction (ii) 9A in clockwise direction (iii) 6 A in anti-clockwise direction (iv) 6 A in the clockwise direction.

The correct answer is -(iv) 6A in the clockwise direction