An object is situated 40 cm from a convex mirror. when a plane mirror is inserted between an object and a concave mirror at a distance 32 cm from the object the images in the two mirrors coincide what is the radius of curvature of the convex mirror.

Ametal ring 4.20 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. these magnets produce an initial uniform field of 1.12 t between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.240 t/s . (a) what is the magnitude of the electric field induced in the ring? (b) in which direction (clockwise or counterclockwise) does the current flow as viewed by someone on the south pole of the magnet?