Two metallic spheres S1 and S2 are made of the same material and have got identical surface finish. The mass of S1 is thrice that of S2. Both spheres are heated to same high temperature and placed in the same room having lower temperature . The ratio of the initial rate of cooling of S1 to that of S2 is:
1/3
If the temperature of the sun increases from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on earth to what it was previously, will be:
4
16
32
64
A block of steel heated to 100oC is left in a room to cool. Which of the curves shown in the figure, represents the correct behaviour ?
A
B
C
None
A block of ice at - 10oC is slowly heated and converted to steam at 100oC. Which of the following curves represents the phenomenon qualitatively ?
The temperature coefficient of resistance of a wire is 0.00125oC-1. At 300 K, its resistance is 1 Ω. The resistance of the wire will be 2 Ω at which temperature ?
1,154 K
1,100 K
1,400 K
1,127 K
Assuming the sun to be a spherical body of radius R at a temperature of TK, evaluate the total radiant power, incident on earth, at a distance r from the sun ?
Which of the following is closer to a black body ?
Blackboard paint
Green leaves
Black holes
Red roses
A black body has maximum wavelength λm at 2000 K. Its corresponding wavelength at 3000 K will be
During constant temperature, we feel colder on the day when the relative humidity is
85%
60%
50%
25%
According to Newton's law of cooling, the rate of cooling of a body is proportional to , where is the difference of the temperature of the body and the surroundings and n is equal to:
Two
Three
Four
One
