Question

An equilateral triangle of side 'a' carries a current i then find out the magnetic field at point P which is vertex of triangle

• A. $\frac { \mu _ { 0 } \mathrm { i } } { 2 \sqrt { 3 } \pi \mathrm { a } }$ ⊗
• B. ◉
• C. ◉
• D. Zero

Answer 1

Answer: (B)

◉

Answer 2

As shown in the following figure magnetic field at P due to side 1 and side 2 is zero.

Magnetic field at P is only due to side 3,

Which is $B _ { 1 } = \frac { \mu _ { 0 } } { 4 \pi } \cdot \frac { 2 i \sin 30 ^ { \circ } } { \frac { \sqrt { 3 } a } { 2 } }$◉

$= \frac { \mu _ { 0 } } { 4 \pi } \cdot \frac { 2 i } { \sqrt { 3 } a }$ ◉ =$\frac { \mu _ { 0 } i } { 2 \sqrt { 3 } \pi a }$◉