What is absorbing power and reflecting power of a perfect black body?

Q: The inside of Ferry's black body is blackened but nickel polished outside, Why?

A: A blackbody has a spectrum which depends only on temperature. The easiest way to achieve this is to…

Q: Consider an opaque body capable of absorbing red light and illuminated by: Yellow light

A: given: body absorbs = red light (R) illuminated by   = yellow light  (Y)

Q: Which color of light has the higher energy per photon, violet or red?

A: The energy of photon be defined as, E=hν

Q: Explain briefly how the photoelectric effect is used in the operation of at least two of the…

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Q: Why is the color of the clear sky is blue?

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Q: As an object is heated, the peak in its thermal emission spectrum may shift out of the visible part…

A: According to Wien's displacement law λT=a constant

Q: what part of the electromagnetic spectrum is most absorbed by water?

A: A material absorbs light when the natural frequency of oscillation of that material matches with the…

Q: Name the four colours of spectrum of white light which have wavelength longer than blue light.

A: White light consist of seven colours namely, violet, indigo, blue, green, yellow, orange and red in…

Q: Why do opaque materials become warmer when light shines on them?

A: The incident light energy on the material of the opaque substances vibrates the atoms r molecules of…

Q: Name the material of prism required for obtaining the spectrum of (a) ultraviolet light (b) infrared…

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Q: Is it necessary that that every black coloured objects should be considered a blackbody?

A: A perfect black body is a body that absorbs all the radiation that falls on it.

Q: For a blackbody object of given volume, which shape will it emit the least radiation? Why?

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Q: Which colours of light emitted from an atom is associated with the most and least change in energy

A: We know, Energy = Planck's constant * frequency

Q: Which of the following physicists discovered that white light was a combination of all colours of…

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Q: could a light bulb approximate a blackbody?

A: Black body absorbs radiation of all wavelength which are incident on it. Black body does not reflect…

Q: Why does a good emitter of heat radiation appear black at room temperature?

A: A good emitter of heat radiation appears black at room temperature because good emitters are having…

Q: Why will the leaves of a red rose be warmed more than the petals when illuminated with red light?

A: The petals of a red rose reflect all the red light coming from the source, whereas the leaves absorb…

Q: Who was the first person to obtain the spectrum of sunlight?

A: In 1666, Sir Issac Newton performed prism experiment to obtain the spectrum of sunlight. In his…

Q: Why is a red-hot object cooler than a white-hot one of the same material?

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Q: Lamp black and platinum black are used as perfect black body one for the absorption of heat…

A: an ideal black body , which absorbs all types of radiations falls on it. this is true for the…

Q: How does the difference in energy levels relate to energy of the photon that is emitted by a…

A: The energy of a photo emitted during transition between two energy levels will be equal to the…

Q: We see flash earlier than thunder. Discuss.

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Q: When something is painted red, what color is most absorbed?

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Q: About how much of the measured electromagnetic spectrum does light occupy?

A: An electromagnetic spectrum consists of wise range of waves.  Gamma Rays, X rays, Ultraviolet rays,…

Q: How does incident light that falls on an object affect the motion of electrons in the atoms of the…

A: When light with a certain frequency is incident on an object it can be absorbed, reflected or…

Q: How does the ditrection of polarization of light compare with the direction of vibration of the…

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Q: What determines whether a material is transparent or opaque?

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Q: Why will body emit more radiation under similar conditions, a black body or a polished body?

A: According to the Stefan-Boltzmann law, the energy radiated is

Q: How is the wavelength of light correlated with its energy content?

A: The energy of light can be expressed as E=hν

Q: Why does a body emit radiations of all wavelengths and not for a particular wavelength?

A: Wavelength – When we consider a point on a single wave, then the measurement of the distance between…

Wien's displacement law

Students often get confused between Wien's displacement law and Planck's radiation law. Although both are historically related, yet they are conceptually different. Planck's law helps determine the spectrum of a blackbody, while Wien's law determines the relationship between peak wavelength and temperature.