Magnetic Effects Of Current Question 15
Question 15 - 30 January - Shift 2
As shown in the figure, a current of $2 A$ flowing in an equilateral triangle of side $4 \sqrt{3} cm$. The magnetic field at the centroid $O$ of the triangle is :
(Neglect the effect of earth’s magnetic field.)
(1) $4 \sqrt{3} \times 10^{-4} T$
(2) $4 \sqrt{3} \times 10^{-5} T$
(3) $\sqrt{3} \times 10^{-4} T$
(4) $3 \sqrt{3} \times 10^{-5} T$
Show Answer
Answer: (4)
Solution:
Formula: Magnetic field due to a straight wire
$d \tan 60^{\circ}=2 \sqrt{3}$
$d=2 cm$
$B=3 \times \frac{\mu_0 i}{2 \pi d} \sin 60^{\circ}$
$=3 \times \frac{2 \times 10^{-7} \times 2}{2 \times 10^{-2}} \times \frac{\sqrt{3}}{2}$
$=3 \sqrt{3} \times 10^{-5}$
