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प्रश्न
Name the scientist who discovered Infra-red waves
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उत्तर
Hershell
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संबंधित प्रश्न
Identify the part of the electromagnetic spectrum which is:
produced by bombarding a metal target by high speed electrons.
Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. State the part of the electromagnetic spectrum to which each belongs.
(a) 21 cm (wavelength emitted by atomic hydrogen in interstellar space).
(b) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen; known as Lamb shift).
(c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe].
(d) 5890 Å - 5896 Å [double lines of sodium]
(e) 14.4 keV [energy of a particular transition in 57Fe nucleus associated with a famous high resolution spectroscopic method (Mössbauer spectroscopy)].
Name the high energetic invisible electromagnetic waves which help in the study of the structure of crystals
Give one use of microwaves.
50% of the X-ray coming from a Coolidge tube is able to pass through a 0.1 mm thick aluminium foil. The potential difference between the target and the filament is increased. The thickness of the aluminium foil that will allow 50% of the X-ray to pass through will be
Name the radiation of the electromagnetic spectrum which is used for the following:
Radar and Give the frequency range.
If the Earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.
The half-value thickness of an absorber is defined as the thickness that will reduce exponentially the intensity of a beam of particles by a factor of 2. The half-value thickness in (µm) for lead assuming X-ray beam of wavelength 20 pm, µ = 50 cm-1 for X-rays in lead at wavelength λ = 20 pm, is ______ µm.
Name one radiation having the wavelength longer than the wavelength of these radiations.
