Home
Class 11
PHYSICS
Assertion : A body that is a good radiat...

Assertion : A body that is a good radiator is also a good absorber of radiation at a given wavelength.
Reason : According to Kirchhoff's law the absorptivity of a body is equal to its emissivity at a given wavelength

A

If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.

B

If both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.

C

If Assertion is true but Reason is false

D

If Assertion is false but Reason is true.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze the assertion and the reason provided, and determine their validity based on the principles of physics, particularly Kirchhoff's law. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "A body that is a good radiator is also a good absorber of radiation at a given wavelength." - This means that if a material can effectively emit radiation (as a good radiator), it should also be able to absorb radiation efficiently at the same wavelength. 2. **Understanding the Reason**: - The reason provided is "According to Kirchhoff's law, the absorptivity of a body is equal to its emissivity at a given wavelength." - Kirchhoff's law states that for a body in thermal equilibrium, the amount of radiation it emits (emissivity) is equal to the amount of radiation it absorbs (absorptivity) at a specific wavelength. 3. **Applying Kirchhoff's Law**: - From Kirchhoff's law, we can conclude that if a body has high emissivity (is a good radiator), it must also have high absorptivity (is a good absorber) at that wavelength. - Therefore, both the assertion and the reason are consistent with each other. 4. **Conclusion**: - Since both the assertion and the reason are true, and the reason correctly explains the assertion, we can conclude that the statement is valid. - The correct answer is that both the assertion and the reason are true, and the reason is the correct explanation of the assertion. ### Final Answer: Both the assertion and the reason are true, and the reason is the correct explanation of the assertion. ---
To solve the question, we need to analyze the assertion and the reason provided, and determine their validity based on the principles of physics, particularly Kirchhoff's law. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "A body that is a good radiator is also a good absorber of radiation at a given wavelength." - This means that if a material can effectively emit radiation (as a good radiator), it should also be able to absorb radiation efficiently at the same wavelength. ...
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • CALORIMETRY AND HEAT TRANSFER

    DC PANDEY ENGLISH|Exercise Match the columns|4 Videos

  • CALORIMETRY AND HEAT TRANSFER

    DC PANDEY ENGLISH|Exercise Medical entrance s gallery|38 Videos

  • CALORIMETRY AND HEAT TRANSFER

    DC PANDEY ENGLISH|Exercise Taking it together|51 Videos

  • CALORIMETRY & HEAT TRANSFER

    DC PANDEY ENGLISH|Exercise Level 2 Subjective|14 Videos

  • CENTRE OF MASS

    DC PANDEY ENGLISH|Exercise Medical entrances gallery|27 Videos

Similar Questions

Explore conceptually related problems

Assertion : Perspiration from human body helps in cooling the body. Reason : A thin layer of water on the skin enhances its emissivity.

A body, which emits radiations of all possible wavelengths, is known as

Knowledge Check

  • Assertion: When distance between bodies is doubled and also mass of each body is also doubled, gravitational force between them remains the same. Reason: According to Neweton's law gravitational, force is directely proportional to mass of bodies and inversely proportional to square of distance between them.

    A
    If both assertion and reason are true and reason is the correct explanation of assertion
    B
    If both assertion and reason are truebut reason is not the correct explanation of assertion
    C
    If assertion is true but reason is false
    D
    If both assertion and reason are false.

    • Similar Questions

    Explore conceptually related problems

    Assertion(A) Black body is an ideal body that emits and absorbs radiations of all frequencies. Reason(R) The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature.

    Assertion : All black coloured objects are considered black bodies. Reason : Black colour is a good absorber of heat

    Assertion : When temperature of a body is increased, in radiant energy, number of low wavelength photons get increased. Reason : According to Wien's displacement law lambda_m prop 1/T .

    Assertion : A body can have acceleration even if its velocity is zero at a given instant of time. Reason : A body is momentarily at rest when it reverses its direction of motion.

    Assertion : According to Newton's law, good conductors of elctricity are also conductors of heat. Reason : At a given temperature , e_(lambda) prop a_(lambda) for any body.

    Assertion : A hollow metallic closed container maintained at a uniform temperature cab act as a source of black body radiation. Reason : All metals act as a black body.

    These question consists of two statements each printed as Assertion and Reason. While answering these question you are required to choose any one of the following five responses. Assertion: If a body is good absorber of green light then it will be good reflector or red light. Reason: At a given temperature, the ratio of emissive power to absorptive power is same for all substances.

    Home
    Profile