railway RRB JE (CBT I + CBT II) Mock Test 2024 Heat Transfer Radiation Properties of Surface Emission
Which of the following statements are correct?
1) If any body radiate equally in all directions, then it is called a diffuse body.
2) For diathermonous bodies, absorptivity is zero and transmissivity is zero.
3) For a perfect black body, transmissivity is zero and emissivity is one.
4) The emissivity and absorptivity of a real surface are equal for radiation with identical temperatures and wavelengths.
1
2,3 and 4
2
1, 2 and 4
3
1, 3 and 4
4
1, 2, 3 and 4