CBSE
Multiple Choice QuestionsFor 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
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
An 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
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
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
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
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
Heat produced (cals) in a resistance R when a current I amperes flows through it for t seconds is given by the expression
