List of top Physics Questions on Magnetic Field Due To A Current Element, Biot-Savart Law asked in KCET

The correct Biot-Savart law in vector form is

A current I flows in the anticlockwise direction through a square loop of side a lying in the xoy plane with its center at the origin. The magnetic induction at the center of the square loop is

Two concentric coils each of radius equal to $2\, \pi$ cm are placed right angles to each other.If $3\,A$ and $4\,A$ are the currents flowing through the two coils respectively. The magnetic induction $(in\, Wb\, m^{-2})$ at the centre of the coils will be

ABCD is a square loop made of an uniform conducting wire. The current enters the loop at A and leaves at D. The magnetic field is