Dual Nature of Radiation and Matter

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Question

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Question 1 :

Heat energy received by the earth from the sun is due to

1. Convection
2. Radiation
3. Reflection of light
4. Transmission of light
Answer
4929

Question 2 :

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?

1. 1: 4
2. 4: 1
3. 3: 4
4. 4: 3
Answer
4930

Question 3 :

For which of the following process, the thermal conduction is maximum?

1. Combustion
2. Radiation
3. Convection
4. Conduction
Answer
4931

Question 4 :

Rest mass of an electron is 0.51 MeV. If it is given a velocity of 0.8 c, its kinetic energy will be

1. 0.27 MeV
2. 0.34 MeV
3. 0.68 MeV
4. None of these
Answer
4932

Question 5 :

An ideal black body is represented by

1. A metal coated with a black dye
2. A glass surface coated with coal tar
3. A hollow enclosure blackened from inside and having a small hole
4. A lump of charcoal heated to a high temperature
Answer
4933