A circular loop of area 0.04m2 carrying a current of 10A is held with its plane perpendicular to a magnetic field induction 0.4 T Then the torque acting on the circular loop is :
The torque τ acting on a current-carrying loop in a uniform magnetic field is given by the formula: τ=nIABsin‌θ where n is the number of turns of the loop (which is 1 in this case as it's not specified otherwise), I is the current in amperes, A is the area of the loop in square meters, B is the magnetic field strength in teslas, θ is the angle between the normal to the plane of the loop and the magnetic field direction. In this scenario, the plane of the loop is perpendicular to the magnetic field, which means θ=0∘. However, when calculating the torque with the formula above, we must consider that sin‌θ hence becomes sin‌0∘=0. Substituting the given values, with θ=0∘, we get: ‌τ=1×10A×0.04m2×0.4T×sin‌(0∘) ‌τ=0.16×0 ‌τ=0‌Nm Therefore, the torque acting on the circular loop is zero, making Option B the correct answer.