Q.

As shown in the figure, a current of 2 A flowing in an equilateral triangle of side 43cm. The magnetic field at the centroid O of the triangle is                 [2023]

(Neglect the effect of earth's magnetic field.)

1 43×10-4 T  
2 43×10-5 T  
3 3×10-4 T  
4 33×10-5 T  

Ans.

(4)

d tan 60°=23

d=2 cm

B=3×μ0i2πdsin60°

=3×2×10-7×22×10-2×32

=33×10-5