Question

A charge q coulomb moves in a circle at n revolutions per second and the radius of the circle is r metre. Then magnetic field at the centre of the circle is

• A. $\frac { 2 \pi q } { n r } \times 10 ^ { - 7 }$ N/amp/metre
• B. $\frac { 2 \pi q } { r } \times 10 ^ { - 7 }$ N/amp/metre
• C. $\frac { 2 \pi n q } { r } \times 10 ^ { - 7 }$N/amp/metre
• D. $\frac { 2 \pi q } { r }$ N/amp/metre

Answer 1

Answer: (C)

$\frac { 2 \pi n q } { r } \times 10 ^ { - 7 }$N/amp/metre

Answer 2

The magnetic field at the centre of the circle