Answer:
1.162 x 10^-7 Nm
Explanation:
length of wire, l = 25 cm
l = 2 π r
where, r is the radius of circular loop
25 = 2 x 3.14 x r
r = 3.98 cm
Magnetic field, B = 5.55 mT = 5.55 x 10^-3 T
Current, i = 4.121 mA = 4.21 x 10^-3 A
Torque, τ = i x A x B
τ = 4.21 x 10^-3 x 3.14 x 0.0398 x 0.0398 x 5.55 x 10^-3
τ = 1.162 x 10^-7 Nm
Thus, the maximum torque in the coil is 1.162 x 10^-7 Nm.
