CBSE
Multiple Choice QuestionsAn immersion heater with electrical resistance 7 Ω is immersed in 0.1 kg of water at 20°C for 3 min. If the flow of current is 4 A, what is the final temperature of the water in ideal conditions ? (Specific heat capacity of water = 4.2x 103 Jkg-1 K-1)
28°C
48°C
52°C
68°C
Heat produced (cals) in a resistance R when a current I amperes flows through it for t seconds is given by the expression
The temperature of equal masses of three different liquids A, Band Care 12°C, 19°C and 28°C respectively. The temperature when A and B are mixed is 16°C and when B and C are mixed is 23°C. The temperature when A and C are mixed is
18.2°C
22°C
20.2°C
24.2°C
A 10 Ω electric heater operates on a 110 V line. The rate at which heat is developed in watts is
1310 W
670 W
810 W
1210 W
For a certain thermocouple, if the temperature of the cold junction is 0°C, the neutral temperature and inversion temperatures are 285°C and 570°C respectively. If the cold junction is brought to 10°C, then the new neutral and inversion temperatures are respectively
285°C and 560°C
285°C and 570°C
295°C and 560°C
275°C and 560°C
In which of the following substances does resistance decrease with increase in temperature ?
Copper
Carbon
Constantan
Silver
Which one of the figure gives the temperature dependence of density of water correctly ?
A piece of wood is floating in water. When the temperature of water rises, the apparent weight of the wood will
increase
decrease
may increase or decrease
remain same
An experiment takes 10 min to raise temperature of water from 0°C and 100°C and another 55 min to convert it totally into steam by a stabilized heater. The latent heat of vaporization comes out to be
530 cal/g
540 cal/g
550 cal/g
560 cal/g
A wire is stretched under a force. If the wire suddenly snaps the temperature of the wire
remains the same
decrease
increase
first decrease then increase
