NEET Physics: radiation Practice Questions
15 free multiple-choice questions on radiation (Properties of Solids and Liquids) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Which of the following quantities is related to the rate of radiation transfer per unit area in a specific direction?
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Correct answer: A — Spectral radiance
Spectral radiance describes the radiant energy emitted or transmitted per unit area, per unit solid angle, per unit wavelength.
Q2. In the context of radiation, what term describes the fraction of incident radiation that is absorbed by a surface?
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Correct answer: C — Absorptivity
Absorptivity is the measure of how much of the incident radiation is absorbed by a surface.
Q3. Which surface is considered a perfect absorber of all incident radiation, according to ideal physics models?
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Correct answer: A — a perfect blackbody
A perfect blackbody is defined as an object that absorbs all incident radiation incident upon it and is a perfect emitter of thermal radiation.
Q4. Which type of radiation is primarily associated with the transfer of heat energy between objects without any medium?
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Correct answer: B — Infrared radiation
Infrared radiation is the primary form of electromagnetic radiation used for thermal radiation and heat transfer between objects, especially in the context of solids and liquids.
Q5. Which radiation process involves the emission of electromagnetic waves by a hot object, regardless of whether the object is a black body or not?
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Correct answer: D — Emission
Emission is the process by which objects, especially hot bodies, release energy in the form of electromagnetic radiation.
Q6. Which type of radiation is emitted by all objects above absolute zero temperature?
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Correct answer: B — Thermal radiation
All objects above absolute zero emit thermal radiation, which is a form of electromagnetic radiation.
Q7. If a body is a perfect black body, what is the relationship between the energy it absorbs and the energy it radiates based on the Stefan-Boltzmann law?
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Correct answer: D — Energy absorbed = Energy radiated
For a perfect black body, the energy absorbed is entirely converted to radiation emitted, following the principle that radiation is emitted proportional to the fourth power of temperature.
Q8. For radiation to be efficiently transferred from a hotter body to a colder body, what is the necessary condition regarding the surface interaction?
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Correct answer: D — The surfaces must be in thermal equilibrium.
Heat transfer by radiation is most effective when there is a temperature gradient, meaning the bodies are not in thermal equilibrium.
Q9. When radiation passes through a transparent medium, what change typically occurs to the spectral distribution of the radiation?
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Correct answer: C — The wavelength is inversely proportional to the medium's refractive index
When radiation passes through a medium, changes occur based on the material's properties (like refractive index), which affects the spectral characteristics (spectral radiance).
Q10. A body that absorbs all incident radiation incident upon it is defined as a:
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Correct answer: A — Black body
A black body is an idealized object that absorbs all incident radiation; thus, it is the standard reference for radiation calculations.
Q11. Which quantity is directly proportional to the total energy radiated by a black body in a given time, according to the Stefan-Boltzmann Law?
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Correct answer: C — Fourth power of the absolute temperature
The Stefan-Boltzmann Law states that the total energy radiated per unit time by a black body is directly proportional to the fourth power of its absolute temperature (T⁴).
Q12. Radiation emitted by a perfect blackbody is characterized by which property?
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Correct answer: B — It emits the maximum possible radiation
A perfect blackbody is an ideal emitter and absorber, meaning it radiates the maximum possible energy for a given temperature.
Q13. The property that describes how effectively a surface emits radiation is known as:
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Correct answer: C — Emissivity
Emissivity (ε) is the ratio of the radiation emitted by a surface to the radiation incident upon that surface.
Q14. Consider a body that absorbs all incident radiation. What property does this body exhibit regarding thermal radiation?
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Correct answer: A — It acts as a perfect absorber.
A body that absorbs all incident radiation is known as a perfect absorber, meaning its absorptivity is 1 (or α=1).
Q15. What is the term used to describe the radiation emitted by an ideal body that absorbs all incident radiation and re-radiates it as thermal radiation?
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Correct answer: D — Black body
A black body is an idealized object that absorbs all incident radiation and emits radiation based solely on its temperature, perfectly radiating energy.
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