Adding salt raises the boiling point of water, which allows food to cook at higher temperature. The higher the temperature, the higher the rate of heat transfer between the food and water, thus it cooks more quickly.

Correct Option: A

Adding salt raises the boiling point of water, which allows food to cook at higher temperature. The higher the temperature, the higher the rate of heat transfer between the food and water, thus it cooks more quickly.

Relative density is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material.So, it is a dimensionless quantity and has no unit.

Correct Option: D

Relative density is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material.So, it is a dimensionless quantity and has no unit.

A nanometer is a unit of spatial measurement that is 10-9 meter, or one billionth of a meter. It is often used to express dimensions on an atomic scale. It is commonly used in nanotechnology, the building of extremely small machines.

Correct Option: C

A nanometer is a unit of spatial measurement that is 10-9 meter, or one billionth of a meter. It is often used to express dimensions on an atomic scale. It is commonly used in nanotechnology, the building of extremely small machines.

A single solar cell can produce only a small amount of electricity. In those cases where more electrical power is needed, a large number of solar cells are joined in series. This group of solar cells is called a ‘solar cell panel’. Thus, a solar cell panel consists of a large number of solar cells joined together in a definite pattern.

Correct Option: C

A single solar cell can produce only a small amount of electricity. In those cases where more electrical power is needed, a large number of solar cells are joined in series. This group of solar cells is called a ‘solar cell panel’. Thus, a solar cell panel consists of a large number of solar cells joined together in a definite pattern.

When fast moving electrons strike on high atomic weight substance, X – ray is produced. In contrast, Photoelectric effect takes place when radiation of sufficient frequency incident on the metal surface and electrons are emitted. Hence, X – ray is the inverse phenomenon of photoelectric effect.

Correct Option: D

When fast moving electrons strike on high atomic weight substance, X – ray is produced. In contrast, Photoelectric effect takes place when radiation of sufficient frequency incident on the metal surface and electrons are emitted. Hence, X – ray is the inverse phenomenon of photoelectric effect.