Question

Ratio of magnetic field at the centre of a current carrying coil of radius R and at a distance of 3R on its axis is-

• A. 10 $\sqrt { 10 }$
• B. 20 $\sqrt { 10 }$
• C. 2 $\sqrt { 10 }$
• D. $\sqrt { 10 }$

Answer 1

Answer: (A)

10 $\sqrt { 10 }$

Answer 2

= $\left( \frac { \mathrm { R } ^ { 2 } + \mathrm { x } ^ { 2 } } { \mathrm { R } ^ { 2 } } \right) ^ { 3 / 2 }$