The radiator of a car contains 20 litre of water. If the motor supplies calorie heat to it, then rise in temperature will be :
10o C
20o C
100o C
103 oC
Calorie is defined as the amount of heat required to raise temperature of 1 g of water by 1oC and it is defined under which of the following conditions ?
From 14.5oC to 15.5oC at 760 mm of Hg
From 98.5oC to 99.5oC at 760 mm of Hg
From 13.5oC to 14.5oC at 76 mm of Hg
From 3.5oC to 4.5oC at 76 mm of Hg
The sprinkling of water reduces slightly the temperature of a closed room because:
Temperature of water is less than that of the room
Specific heat of water is high
Water has large latent heat of vaporisation
Water is bad conductor of heat
The unit of Stefan's constant is :
Wm-2K-1
WmK-4
Wm-2K-4
Nm-2K-4
Three disc A, B and C having radii 2 m, 4 m and 6 m respectively are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are 300 nm, 400 nm and 500 nm respectively. The powers radiated are QA, QB and QC respectively.
QA is maximum
QB is maximum
QC is maximum
QA = QB = QC
A black body at a temperature of 227oC radiates heat at the rate of 20 cal m-2s-1. When its temperature rises to 727oC, the rate of heat radiated will be
40 cal m-2s-1
160 cal m-2s-1
320 cal m-2s-1
640 cal m-2s-1
Which of the following is closer to a black body ?
Blackboard paint
Green leaves
Black holes
Red roses
Two identical rods are connected between two containers. One of them is at 100oC and another is at 0oC. If rods are connected in parallel then the rate of melting of ice is q1 g/sec. If they are connected in series then the rate is q2. The ratio q2/q1 is:
2
4
1/2
1/4
Let 50 g of ice at 0oC is mixed with 50 g of water at 80oC, final temperature of mixture of will be:
0oC
40oC
60oC
4oC
The volume of a liquid is 830 m3 at 30o C and it is 850 m3 at 90o C. The coefficient of volume expansion of the liquid is