Physics - Study Mode
[#231] Water has maximum density at
Correct Answer
(C) 4°C
Explanation
Solution: An especially notable irregular maximum density is that of water, which reaches a density peak at 3.98°C (39.16°F) approximately 4 o C.
[#232] When water freezes its density
Correct Answer
(A) Decreases
Explanation
Solution: When water freezes its density decreases. Water at ordinary temperatures contracts and increases in density as it is cooled, like most substances. But at about 4°C it reaches a maximum density and then decreases in density as it approaches the freezing point.
[#233] Which of the following are methods of heat transfer?
Correct Answer
(A) Convection
Explanation
Solution: The three types of heat transfer Heat is transfered via solid material (conduction), liquids and gases (convection), and electromagnetical waves (radiation). Heat is usually transfered in a combination of these three types and seldomly occurs on its own.
[#234] Heat energy is transferred by conduction whenever molecules
Correct Answer
(A) Collide each other
Explanation
Solution: Conduction is heat transfer through stationary matter by physical contact.
[#235] Refrigeration is a process which
Correct Answer
(B) Slows down the bacterial growth
Explanation
Solution: Refrigeration is the process by which artificial cooling takes place. The temperature is kept lower than the normal during the process. It stops the growth of the bacteria thereby keeping the food perishable and edible.