sec 2 science revision #7

Which of the following statements is incorrect about heat transfer?

• Heat transfer cannot take place in a vacuum.

• Convection cannot take place in solids.

• Solids are better conductors of heat compared to liquids and gases.

• Convection involves the movement of the medium itself during the processof heat transfer

• The match reflects heat away.

• The air does not conduct heat well to light up the match head.

• The flame is still not hot enough to cause the match to light up.

• There is no convection in the air to light up the match.

• The speed increases as the density of the substance increases.

• The speed is greater in less dense substances.

• The speed is greater in metals than in gases.

• The speed is greatest in the densest metal.

• A

• B

• C

• D

In which of the following is a kilowatt-hour of electrical energy used?

• A 50 W electric fan used for 2 hours.

• A 500 W computer used for 1 hour.

• A 3000 W heater is used for 20 minutes.

• Two 100 W lamps used for 30 minutes.

• K, L, M, N

• L, N, M, K

• M, K, N, L

• N, K, L, M

• A

• B

• C

• D

Nadia is stung by a bee. Her mother rubs dilute acid on her wound to relieve the pain.

What can you infer from this observation?

• The bee sting contains an element which reacts with the acid.

• The bee sting is acidic.

• The bee sting is alkaline.

• The bee sting is neutral.

• condensation

• conduction

• convection

• radiation

Where would you store fried rice to keep it as hot as possible?

• metal box

• metal plate

• plastic box

• porcelain plate