The magnetic field at the centre of ring carrying electric current is ____ of area of the ring.

Options

A. inversely proportional to square root
B. inversely proportional
C. directly proportional
D. directly proportional to square root

Answer

A

Explanation

`B=(mu_(0)I)/(2a)`
But `A=pia^(2)`
`thereforea=(A/pi)^(1/2)`
`thereforeB=(mu_(0)Ixxpi^(1/2))/(2xxA^(1/2))`
`thereforeBprop1/A^(1/2)" "[because"Other terms are constant"]`