Question

1. Heat radiations travel with a speed:
(a) less than the speed of light
(b) equal to the speed of light
(c) greater than the speed of light.
(d) equal to the speed of sound.
2. Heat loss from a surface by radiation can be minimized by :
(a) polishing the surface
(b) blackening the surface
(c) creating vacuum around it
(d) keeping in dark
3. The vacuum is kept in between the walls of vacuum flask to reduce the heat less by:
(a) conduction only
(b) convection and radiation
(c) radiation only
(d) conduction and convection
4. Good absorbers are .................. radiators.
(a) good
(b) poor (c) both 1 and 2
(d) none of these
5. A device in which heat losses are minimized due to conduction, convection and
radiation is .......
(a) thermometer
(b) bimetallic strip
(c) thermos flask
(d) solar cooker
6.
Highly polished surfaces are ................... absorbers of heat, but ...
reflectors.
(a) good, poor
(b) poor, good
(c) neither good, nor poor
(d) none of these
7. Which type of heat transfer can occur in a vacuum ?
(a) conduction (b) convection (c) radiation (d) none of these
8. Statement A Heat radiations can travel through vacuum with the speed 3 x 108 m/s
Statement B: Black surfaces are better absorbs of heat than white ones.
(a) both the statements are true. (b) both the statements are false.
(C) only statement A is true,
(d) only statement B is true.





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Answer 1

Explanation:

1) Less than speed of Light

2) Blackening the surface as it absorbs heat

3) Sorry I don't know this

4) Good radiators

5) Thermos Flask

6) Poor , Good

7) Sorry I don't know this

8) Only statement B is true