Physics Questions

The given statement, The heat from the sun reaches earth through Convection is FALSE.

Heat from the sun actually reaches the earth through Radiation. The process occurs through electromagnetic radiation, specifically, in which molecules are warmed when the heat reaches them, and these molecules then warm other molecules touching them, which continues until we feel the sun's heat.

For an atom to emit X-rays it should have difference in energy levels

Both the floor and the carpet have the same temperature as both are exposed to the same atmosphere. But the former conducts away the heat from the feet better than the carpet as the latter is a non-conductor. So the feet losing more heat, the floor appears cooler to the feet.

Low Voltage Cables are used to supply power for use up to 1.1 kV.

Water has the maximum density at 4oC. So at this temperature, it sinks down to bottom and stays here. If it cools further, it will become less dense and move up. So while the upper layers can cool enough to form ice, the bottom layers remain as water at  4oC .  

Therefore, (C) is correct.