The brightness-of a star depends on its

• size and temperature only

• size and distance from the earth

• size, temperature and mass

• size, temperature and distance from the earth

When a solid is heated, it turns directly into a gas. This process is called

• Condensation

• Evaporation

• Sublimation

• Diffusion

3.

Which one of the following statements with regard to expansion of materials due to heating is not correct?

• As ice melts, it expands uniformly up to 4°C

• Mercury thermometer works using the principle of expansion due to heating

• Small gap is kept between two rails to allow for expansion due to heating

• The length of metallic wire increases when its temperature is increased

Statement I and Statement II. You are to examine these two statements carefully and select the answers to these items using the code given below :

Statement I: While putting clothes for drying up, we spread them out.

Statement II: The rate of evaporation increases with an increase in surface area.

• Both the statements are individually true and Statement II is the correct explanation of Statement I.

• Both the statements are individually true but Statement II is not the correct explanation of Statement I

• Statement I is true but Statement II is false

• Statement I is false but Statement II is true

Statement I and Statement II. You are to examine these two statements carefully and select the answers to these items using the code given below :

Statement I: Due to diffused or irregular reflection of light, a closed room gets light even if no direct sunlight falls inside the room.

Statement II: Irregular reflection, where the reflected rays are not parallel, does not follow the laws ofreflection

• Both the statements are individually true and Statement II is the correct explanation of Statement I.

• Both the statements are individually true but Statement II is not the correct explanation of Statement I

• Statement I is true but Statement II is false

• Statement I is false but Statement II is true

A person stands on his two feet over a surface and experiences a pressure P. Now the person stands on only one foot. He would experience a pressure of magnitude.

• 4 P

• P

• ¹/₂ P

• 2 P

A deep sea diver may hurt his ear drum during diving because of

• lack of oxygen

• high atmospheric pressure

• high water pressure

• All of the above

When you walk on a woollen carpet and bring your finger near the metallic handle of a door an electric shock is produced. This is because

• charge is transferred from your body to the handle

• a chemical reaction occurs when you touch the handle

• the temperature of the human body is higher than that of the handle

• the human body and the handle arrive at thermal equilibrium by the process

Which one among the following does not wet the walls of the glass vessel in which it is kept?

• Water

• Alcohol

• Mercury

• Phenol

When heat rays are reflected from Earth, gases like Carbon dioxide, Nitrous oxide do not allow them to escape back to the space causing our planet to heat up. These gases are known as

• Noble gas

• Green-house gas

• Hot gas

• Blue gas