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प्रश्न
State three properties of infrared radiations similar to that of visible light.
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उत्तर
(i) Infrared radiations and visible light both travel in a vacuum with a speed of 3 × 108 ms−1.
(ii) Both the infrared radiations and the visible light obey the laws of reflection and refraction.
(iii) Both the infrared radiations and the visible light are electromagnetic waves.
संबंधित 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)].
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
Can Lα X-ray of one material have shorter wavelength than Kα X-ray of another?
Why is exposure to X-rays injurious to health but not exposure to visible light, when both are electromagnetic waves?
Find the energy, the frequency and the momentum of an X-ray photon of wavelength 0.10 nm.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The distance between the cathode (filament) and the target in an X-ray tube is 1.5 m. If the cutoff wavelength is 30 pm, find the electric field between the cathode and the target.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
State the name and the range of wavelength of the invisible electromagnetic waves beyond the red end of the visible spectrum.
Name one radiation having the wavelength longer than the wavelength of these radiations.
What is the nature of all electromagnetic waves?
Which group of activities uses radio waves?
