A square loop of side is fixed along one edge so that it can rotate about that edge…

PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

A square loop of side 0.20 m0.20\,\text{m} is fixed along one edge so that it can rotate about that edge in a uniform magnetic field of magnitude 0.30 T0.30\,\text{T} which is perpendicular to the axis of rotation. The loop starts from a position in which its plane is perpendicular to the field, and it rotates with a constant angular velocity of 20 rad s−120\,\text{rad s}^{-1} about the fixed edge. (i) Derive an expression for the magnetic flux through the loop as a function of time tt. (ii) Calculate the average value of the magnetic flux through the loop over the first π2 ⋅ 20\dfrac{\pi}{2\,\cdot\,20} seconds of rotation (i.e., during the first quarter revolution).

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