Physics - Study Mode

[#1026] Water is not suitable as a calorimetric substance because it :
Correct Answer

(A) Has high specific heat

Explanation

Solution: The specific heat of water is higher than all other common substances. Hence, water is used for heating purposes (as in hot water bottles) and for cooling purposes (as in radiators of cars). Off all the liquids, mercury has the lowest specific heat due to which it is used as a thermometric liquid .

[#1027] Water is used in car radiator because of its
Correct Answer

(C) High specific heat capacity

Explanation

Solution: Water is used as a coolant in automobiles radiators because it has high specific heat capacity. So, it absorbs a large amount of heat for a degree rise in temperature.

[#1028] How much mechanical work must be done to completely melt 1 gram of ice at 0°C ?
Correct Answer

(B) 80 J

Explanation

Solution: It takes 80 calories to melt 1 gram of ice. If 1 g of ice (at 0 degrees Celsius) is given 80 calories, it will melt and the final temperature of the water will be 0. Freezing water at 0 degrees Celsius: It also takes 80 calories to freeze 1 gram of water.

[#1029] Water pipes in hilly areas often burst on a cold frosty night, because
Correct Answer

(B) Water in the pipes freezes and on freezing water expands, so pipes break

Explanation

Solution: Water pipes burst because the water inside them expands is it gets close to freezing, and this causes an increase in pressure inside the pipe.

[#1030] Which physical quantity is measured in 'siemens'?
Correct Answer

(B) Electrical conductance

Explanation

Solution: The siemens (symbol: S) is the derived unit of electric conductance, electric susceptance, and electric admittance in the International System of Units (SI).