Radiation

IMPORTANT

Radiation: Overview

This Topic covers sub-topics such as Greenhouse Effect, Wien's Displacement Law, Stefan's Constant, Radiant Energy, Thermal Radiation, Spectrum of Radiation, Ideal Black Body, Stefan's Law of Radiation and, Properties of Thermal Radiation

Important Questions on Radiation

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The spectrum of thermal radiation contains:

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The intensity of radiation near a given wavelength is plotted against the wavelength for different temperatures. The peak of the curve is shifted in negative X-direction along the axis of wavelength with the increase in temperature.

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List the gases responsible for the greenhouse effect.

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The greenhouse effect is caused by Accumulation of CO2  in the atmosphere

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Sun's radiant energy is utilized by

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The Radiant energy of the sun results from _____.

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A spherical body of area A and emissivity e=0.6 is kept inside a perfectly black body. Energy radiated per second by the body at temperature T is

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The wavelength of maximum intensity for emitted radiation from a source is 11×105 cm.  The temperature of this source is n times the temperature of some other source for which the wavelength at maximum intensity is known to be 5.5×105 cm. Find the value of n.

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The walls of a thermos flask is painted with silvery paint in order to avoid heat transfer by the process of radiation. 

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In a thermos flask, the transfer of heat does not occur through the process of -

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Which of the following statement is correct

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Thermos flask is used to prevent heat loss due to 

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The silvered surface in thermos flask will reduce heat lose by _____.

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What is  the Green house effect?

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Among the gasses which are considered as greenhouse gas.

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No medium is required for transfer of heat by the process of thermal _____.

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A black body is defined as a perfect absorber of radiations. It may or may not be a perfect emitter of radiations.

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A steady current is passing through a cylindrical conductor of radius r placed in vacuum. Assuming Stefan's law of radiation, steady temperature will be proportional to

HARD
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Three very large plates of same area are kept parallel and close to each other. They are considered as ideal black surfaces and have very high thermal conductivity. First and third plates are maintained at absolute temperatures 2 T and 3 T respectively. Temperature of the middle plate in steady state is

HARD
IMPORTANT

The vacuum in the middle of a double-layered glass in the thermos is used to prevent which mode of transfer of heat?