A perfectly black body MCQ
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If you are looking for Multiple Choice Questions on a perfectly black body Here we collected some important MCQs on a perfectly black body for you. The MCQ questions on the black body included in this page have been selected based on the popular questions asked in various competitive exams over the years.
MCQ on the Black body
1. The emissivity of a perfectly black body is______
(a) 0
(b) 1
(c) 2
(d) 5
Answer: B
2. A perfect black body is one which______________
(a) Is black
(b) Reflects all heat
(c) Transmits all heat radiations
(d) Absorbs heat radiations of all wavelengths falling on it
Answer: D
3. Four copper plates of the same dimensions are painted. with red, green, white, and black colors. All of them are heated up to a temperature of 300°C and then allowed to cool in the surrounding, which is at room temperature. Which plate would cool at the earliest?
(a) Green
(b) While
(c) Black
(d) Red
Answer: C
4. Good absorbers of heat are________
(a) bad emitters
(b) good emitters
(c) highly polished
(d) good conductors
Answer: B
5. A black body is defined as a body_________
(a) which does not emit any radiation
(b) which absorbs all the radiations, of all wavelengths incident upon it
(c) which absorbs radiations only from the infrared and ultraviolet region
(d) Which emits radiations only in the visible region
Answer: B
6. The emissive power of a body is the quantity of radiant energy emitted by the body_______
(a) per unit time
(b) per unit area
(c) per unit area at a given temperature
(d) per unit area per unit time at a given temperature
Answer: D
7. The SI unit of emissive power is______
(a) joule/ms
(b) watt/m²
(c) watt m²
(d) watt/ m²/second
Answer: B
8. The emissive power of a perfectly black body at 300°C, is 6 watt/m². What is the emissive power of another body having an emissivity of 0.7 and kept at the same temperature?
(a) 2.1 watt/m²
(b) 3.00 watt/m²
(c) 4.2 watt/m²
(d) 3.5 watt/m²
Answer: C
9. A perfect black body is one that______________
(a) Transmits all incident radiations
(b) Absorbs all incident radiations
(c) Reflects all incident radiations
(d) Absorbs, reflects, and transmits all incident radiations
Answer: B