Question

This is what happens to a dc generator when its loop turns 180

- the side of the loop that had current running through it and the side that had current running out would have switched, however the current would have not changed direction. this is because of the communator which allows the current to stay moving in one direction, as it switches the side that had current running in, but now has current running out, will pass the current to the brush opposite of the one that passed current to the loop

SO WHAT HAPPENS WHEN THE LOOP TURNS 90 AND WHY

Answer 1

When the loop is turned by an angle of 90° , the maximum number of magnetic field lines passes through the loop and hence a maximum emf is induced at this orientation. It so because the angle between the magnetic field and the normal to the surface is 0° in such a case , and we know that induced emf = d(B×A×cos )/dt ....(according to Faraday's law).

Therefore Maximum emf is induced if loop is rotated by 90°