Answer:
In first case [tex]\tau =6\times 10^{-3}N/m[/tex], In second case torque = 0
Explanation:
We have given length of the square loop = 5 cm = 0.05 m
So area [tex]A=side^2=0.05^2=2.5\times 10^{-3}m^2[/tex]
Current through the loop = 2 A
Magnetic field B = 1.2 T
We know that expression for flux [tex]\Phi =BAcos\Theta[/tex]
In first case there is maximum flux so [tex]\Theta[/tex] must be zero
So initial torque [tex]\tau=IBAsin\Theta[/tex], here B is magnetic field, I is current and [tex]\Theta[/tex] is angle between magnetic field and area vector.
So [tex]\tau=2\times 1.2\times 2.5\times 10^{-3}cos0=6\times 10^{-3}N/m[/tex]
In second case flux is zero so [tex]\Theta[/tex] must be 90°
So initial torque [tex]\tau=2\times 1.2\times 2.5\times 10^{-3}cos90^{\circ}=0[/tex]