When cathode rays are focused on thin metal foil, it gets heated up to ……………

When alpha -particles are made incident on a thin metal foil most of them pass straight through the foil because .

Assertion:- If your focus on a point closer to your eyes, the radius of curvature of eye lens decreaes. Reason:- When rays are to be focused more strongly, a shorter focal length is needed.

When the heavy weight suspended and removed from the metal wire, it cannot get original length. Why?

A thin wire of length l when heated to a certain temperature increases its length by 1% . A sheet of the same material of area 2lxxl is heated to the same temperature then percentage increase in area will be :-

A thin copper wire of length l metre increases in length by 2% when heated through 10^(@)C . What is the percentage increase in area when a square copper sheet of length l metre is heated through 10^(@)C

A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from.

Assertion: Current is passed through a metallic wire, heating it red. When cold water is poured on half of its portion, then rest of the half portion become more hot. Reason: Resistance decreases due to decrease in tem perature and so current through wire increases.

A metal plate is getting heated. It can be because