Which of the following is the characteristic of a black body?
When the radiations are made to pass through a black body, it undergoes multiple reflections and is completely absorbed. When it is placed in a temperature bath of fixed temperature, the heat radiations will come out. Thus a black body is a perfect absorber and a perfect reflector
The energy distribution is not uniform for any given temperature in a perfect black body. True or false?
At different temperatures, when a perfect black body is allowed to emit radiations, then the distribution of energy for different wavelengths at various temperatures is not uniform.
Rayleigh-Jean’s law hold good for which of the following?
According to this law, the energy distribution is directly proportional to the absolute temperature and is inversely proportional to the fourth power of the wavelength. Therefore longer the wavelength, greater is the energy distribution.
Wien’s displacement law hols good only for shorter wavelength. True or false?
This law states that, the product of the wavelength, corresponding to maximum energy and the absolute temperature, is constant. If ʎ is less, then 1/ʎ will be great. Therefore e(hc/ʎKT) will be great.
Which of the following does not affect the photon?
Photons have no charge. They can interact with charged particles but not with themselves. This is why photons are neutral and not affected by magnetic or electric fields.
What is Compton shift?
When a photon collides with an electron at rest, the photon gives its energy to the electron. Therefore the scattered photon will have higher wavelength compared to the wavelength of incident photon. This shift in wavelength is called Compton shift.
Compton shift depends on which of the following?
From the theory of Compton effect it is deducted that change in wavelength
Δʎ = h/mc (1-cosɵ). This equation shows that, the change in wavelength is independent of the incident radiation as well as the nature of scattering substance. The shift depends only on the angle of scattering.
Which of the following is called as non-mechanical waves?
The waves which travel in the form of oscillating electric and magnetic waves are called electromagnetic waves. Such waves do not require any material for their propagation and are called non-mechanical waves.
Which of the following is associated with electron microscope?
The waves associated with microscopic particles when they are in motion are called matter waves. Electron microscope makes use of the matter waves associated with fast moving electrons.
A radio station broadcasts its programme at 219.3 metre wavelength. Determine the frequency of radio waves if velocity of radio waves is 3×108 m/s.
ʎ = velocity/frequency
Frequency = velocity/ʎ
Therefore, frequency = 1.368×106 Hz