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प्रश्न
Electromagnetic waves of wavelengths λ1, λ2 and λ3 are used in a radar system, in water purifiers and in remote switches of TV, respectively.
- Identify the electromagnetic waves.
- Write one source for each of them.
उत्तर
(i)
- Wavelength λ1 corresponds to Microwaves.
- Wavelength λ2 corresponds to Ultraviolet waves.
- Wavelength λ3 corresponds to Infrared waves.
(ii)
- Source of microwaves: Klystron/magnetron valves.
- Source of ultraviolet waves: Movement of electrons in atoms from higher energy level to lower energy level.
- Source of infrared waves: Vibration of atoms and molecules.
संबंधित प्रश्न
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1019 Hz belong?
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)].
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm Calculate the velocity of the wave.
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(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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What is the wavelength of the wave whose frequency is 1012 Hz? Name the electromagnetic wave.
Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
A car is moving towards a high cliff. The car driver sounds a horn of frequency f. The reflected sound heard by the driver has a frequency 2f. If v be the velocity of sound, then the velocity of the car, in the same velocity units, will be:
In uranium (Z = 92) the K absorption edge is 0.107 Å and the Kα line is 0.126 Å, and the wavelength of the L absorption edge is ______.
