(Originais Teachy 2023) - Question Medium of Physics

A rectangular coil with 100 turns, with a length of 20 cm and width of 10 cm, is positioned near a magnet. Initially, the coil is oriented with its plane parallel to the magnetic field of the magnet, so that the magnetic flux through the coil area is maximum. Then, the coil is rotated 90 degrees around the axis connecting its two shorter sides, assuming a new position perpendicular to the magnetic field. (a) Write the expression for the magnetic flux that crosses the coil as a function of the rotation angle and the magnetic field. (b) Calculate the magnetic flux through the coil in the initial and final positions and compare them. (c) Verify if the magnetic flux is constant or variable during the 90-degree rotation.