Heat travels through vacuum by
(a) Conduction                  (b) Convection
(c) Radiation                     (d) Both (a) and (b)

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

We consider the radiation emitted by the human body. Which of the following statements is true ?

(a) The radiation is emitted only during the day

(b) The radiation is emitted during the summers and absorbed during the winters

(c) The radiation emitted lies in the ultraviolet region and hence is not visible

(d) The radiation emitted is in the infra-red region

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The earth radiates in the infra-red region of the spectrum. The spectrum is correctly given by

(a) Wien’s law                                (b) Rayleigh  law

Concept Questions :-

Difficulty Level:

Pick out the statement which is not true .

(a) IR radiations are used for long distance photography

(b) IR radiations arise due to inner electron transitions in atoms

(c) IR radiations are detected by using a bolometer

(d) Sun is the natural source of IR radiation

Concept Questions :-

Difficulty Level:

A hot and a cold body are kept in vacuum separated from each other. Which of the following cause decrease in temperature of the hot body ?

(b) Convection

(c) Conduction

(d) Temperature remains unchanged

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

For a perfectly black body, its absorptive power is

(a) 1                 (b) 0.5
(c) 0                  (d) Infinity

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Certain substance emits only the wavelengths  and ${\mathrm{\lambda }}_{4}$ when it is at a high temperature. When this substance is at a colder temperature, it will absorb only the following wavelengths ?
(a) ${\mathrm{\lambda }}_{1}$                      (b) ${\mathrm{\lambda }}_{2}$
(c) ${\mathrm{\lambda }}_{1}$ and ${\mathrm{\lambda }}_{2}$          (d)   and ${\mathrm{\lambda }}_{4}$

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

As compared to the person with white skin, the person with black skin will experience
(a) Less heat and more cold            (b) More heat and more cold
(c) More heat and less cold             (d) Less heat and less cold

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Relation between emissivity e and absorptive power a is (for black body)
(a) e = a                     (b) $\mathrm{e}=\frac{1}{\mathrm{a}}$
(c) $\mathrm{e}={\mathrm{a}}^{2}$                     (d) $\mathrm{a}={\mathrm{e}}^{2}$

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which of the following statements is wrong ?

(a) Rough surfaces are better radiators than smooth surface

(b) Highly polished mirror like surfaces are very good radiators

(c) Black surfaces are better absorbers than white ones

(d) Black surfaces are better radiators than white

Concept Questions :-