Question

A metal bar is being pushed to the right along a U shaped conducting rail in the presence of a constant magnetic field. This induces a clockwise current as shown in the figure below. The green arrow represents the pushing force. In which direction does the original magnetic field point? - Select one: a. Up b. Down c. Into the screen d. Out of the screen e. To the right

Answer 1

We can see as the rail moves towards right the area of the loop is decreasing, now flux =BA where A is the area of the loop so the flux is decreasing. The induced current flows clockwise generating magnetic field into the page so the original magnetic field would also have been into the page and that's why clockwise current is opposing its decrease

So c is correct