Advertisements
Advertisements
प्रश्न
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)].
Advertisements
उत्तर
(b) Radio waves; belongs to the short wavelength end.
(c) Temperature, T = 2.7°K
λm is given by Planck’s law as:
`lambda_"m" = 0.29/2.7` = 0.11 cm
This wavelength corresponds to microwaves.
(d) This is the yellow light of the visible spectrum.
(e) Transition energy is given by the relation,
E = hv
Where,
h = Planck’s constant = 6.6 × 10−34 Js
v = Frequency of radiation
Energy, E = 14.4 K eV
∴ `"v" = "E"/"h"`
= `(14.4 xx 10^3 xx 1.6 xx 10^-19)/(6.6 xx 10^-34)`
= 3.4 × 1018 Hz
This corresponds to X-rays.
संबंधित प्रश्न
Name the parts of the electromagnetic spectrum which is
used to treat muscular strain.
Write in brief, how these waves can be produced.
If the earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1011 Hz belong?
Name the subjective property of light related to its wavelength.
What is the range of the wavelength of the following electromagnetic waves?
(a) Micro waves .
Name the region beyond the red end of the spectrum.
Give one use of ultraviolet radiation.
Give one use of gamma rays.
An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm Calculate the velocity of the wave.
X-ray and visible light travel at the same speed in vacuum. Do they travel at the same speed in glass?
If the current in the circuit for heating the filament is increased, the cutoff wavelength
X-ray incident on a material
(a) exerts a force on it
(b) transfers energy to it
(c) transfers momentum to it
(d) transfers impulse to it.
Consider a photon of continuous X-ray and a photon of characteristic X-ray of the same wavelength. Which of the following is/are different for the two photons?
Find the cutoff wavelength for the continuous X-rays coming from an X-ray tube operating at 30 kV.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the part of the electromagnetic spectrum which is:
Suitable for radar systems used in aircraft navigation.
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
An e.m. wave exerts pressure on the surface on which it is incident. Justify.
An electron beam is accelerated by a potential difference V to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If λmin is the smallest possible wavelength of X-ray in the spectrum, the variation of log λmin with log V is correctly represented in:
Write two uses of the following radiation.
X-rays
What happens when an electron collides with a positron?
