Radiation - Mechanical Engineering (MCQ) questions and answers

1)   What is the relation between reflectivity (ρ), absorptivity (α) and transmissivity (τ)?

a. ρ – α + τ = 1
b. ρ + α – τ = 1
c. ρ + α + τ = 1
d. ρ – α – τ = 1
Answer  Explanation 

ANSWER: ρ + α + τ = 1

Explanation:
No explanation is available for this question!


2)   The emissivity (ε) can be defined as the ratio of

a. emissive power of real body to the emissive power of black body
b. emissive power of black body to the emissive power of real body
c. reflectivity of real body to emissive power of black body
d. reflectivity of black body to emissive power of real body
Answer  Explanation 

ANSWER: emissive power of real body to the emissive power of black body

Explanation:
No explanation is available for this question!


3)   The radiation from fusion of hydrogen

a. can be achieved on earth's surface
b. cannot be achieved on earth's surface
c. can be achieved on earth's surface at high maintained temperature
d. unpredictable
Answer  Explanation 

ANSWER: cannot be achieved on earth's surface

Explanation:
No explanation is available for this question!


4)   The rate at which the solar energy reaching the earth's atmosphere is called as

a. solar constant
b. radiation constant
c. electromagnetic constant
d. atmospheric constant
Answer  Explanation 

ANSWER: solar constant

Explanation:
No explanation is available for this question!


5)   The radiation energy from the sun is produced by

a. fission reaction
b. fusion reaction
c. both a. and b.
d. none of the above
Answer  Explanation 

ANSWER: fusion reaction

Explanation:
No explanation is available for this question!


6)   How is the cooling at night in coastal areas?

a. the day temperature reduces rapidly at night in coastal areas
b. the day temperature reduces slowly at night in coastal areas
c. the day temperature and a night temperature in coastal areas are similar
d. unpredictable
Answer  Explanation 

ANSWER: the day temperature reduces slowly at night in coastal areas

Explanation:
No explanation is available for this question!


7)   In desert areas, there is large difference between day and night temperatures mainly because of

a. presence of carbon dioxide in air as it acts as barrier for emanating infrared radiation from the earth surface
b. presence of water vapour in air as it acts as barrier for emanating infrared radiation from the earth surface
c. absence of carbon dioxide in air as it acts as barrier for emanating infrared radiation from the earth surface
d. absence of water vapour in air as it acts as barrier for emanating infrared radiation from the earth surface
Answer  Explanation 

ANSWER: absence of water vapour in air as it acts as barrier for emanating infrared radiation from the earth surface

Explanation:
No explanation is available for this question!


8)   Which of the following gases is/are responsible for global warming?

a. Carbon dioxide (CO2)
b. Water vapour (H2O)
c. both a. and b.
d. none of the above
Answer  Explanation 

ANSWER: both a. and b.

Explanation:
No explanation is available for this question!


9)   How is the greenhouse effect experienced on earth?

a. global worming
b. pollution
c. both a. and b.
d. none of the above
Answer  Explanation 

ANSWER: global worming

Explanation:
No explanation is available for this question!


10)   In greenhouse effect, the only infrared radiations

a. are allowed to exit from the interior surface
b. are not allowed to exit from the interior surface
c. cannot absorb heat energy
d. none of the above
Answer  Explanation 

ANSWER: are not allowed to exit from the interior surface

Explanation:
No explanation is available for this question!


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