$2(\frac{τ}{\sqrt3Bi})^{\frac{1}{2}}$
$\frac{2}{\sqrt3}(\frac{τ}{Bi})$
$\frac{1}{\sqrt3}(\frac{τ}{Bi})$
$\frac{2}{\sqrt3}(\frac{τ}{Bi})^{\frac{1}{2}}$
The Correct option is A: $2(\frac{τ}{\sqrt3Bi})^{\frac{1}{2}}$
The current flowing clockwise in the equilateral triangle has a magnetic field in the direction of $\hat{k}$
τ = $BiNAsinθ$
τ = $BiNAsin90^o$
Area of equilateral triangle: $\frac{\sqrt{3}}4 I^2$
τ = $Bi×\frac{\sqrt{3}}4 I^2$
$\therefore I^2 = \frac{4τ}{\sqrt{3} Bi}$ = $2(\frac{τ}{\sqrt3Bi})^{\frac{1}{2}}$