Two thermometers A and B exposed to sunlight. The value of A is painted black but that of B is not painted. The correct statement regarding this case is
|
Two spheres made of same material have radii in the ratio 2: 1. if both the spheres are at same temperature, then what is the ratio of heat radiation energy emitted per second by them? |
Answer |
|
The temperature of a black body is gradually increased. The colour of the body will change from |
Answer |
|
A black body at hot temperature at 227°C radiates heat at a rate of 5 cal/$cm^{2}$s. at a temperature of 727°C the rate of heat radiated per unit area will be |
Answer |
|
Radiation emitted by a surface is directly proportional to |
Answer |
|
A body radiates heat at the ate of 5 cal/m2-s when its temperature is 227°C. the heat radiated by the same body when its temperature is 727°C is |
Answer |
|
Which one of the following constants is not related to radiation? |
Answer |
|
Rate of cooling of body is 0.5°C/min, when the system is 50°C above the surroundings. When a system is 30°C above the surroundings, the rate of cooling will be |
Answer |
|
According to Wien’s law |
Answer |
|
The sun emits light with a maximum wavelength of 510 nm while another star X emits light of maximum wavelength of 350 nm. What is the ratio of the surface temperatures of the sun and the star? |
Answer |
|
A sphere cube and a thin circular plate all made of the same material and having the same mass are initially heated to a temperature of 300°C. which of these cools fastest? |
Answer |