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प्रश्न
State three properties of ultra-violet radiation similar to visible light.
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उत्तर
(i) Ultra-violet radiations can travel in vacuum as the visible light can do, with the speed 3 × 108 ms−1.
(ii) Both the ultra-violet radiations and the visible light are electromagnetic waves.
(iii) Both the ultra-violet radiations and the visible light obey the laws of reflection and refraction.
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)].
Give a reason for the following:
It is necessary to use satellites for long-distance TV transmission. Why?
Name the region beyond the violet end of the spectrum called.
Name of physical quantity which remains same for microwaves of wavelength 1 mm and UV radiations of 1600 Å in vacuum.
Visible light passing through a circular hole forms a diffraction disc of radius 0.1 mm on a screen. If an X-ray is passed through the same setup, the radius of the diffraction disc will be
An X-ray tube operates at 40 kV. Suppose the electron converts 70% of its energy into a photon at each collision. Find the lowest there wavelengths emitted from the tube. Neglect the energy imparted to the atom with which the electron collides.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Answer briefly.
Can we produce a pure electric or magnetic wave in space? Why?
Answer briefly.
Does an ordinary electric lamp emit EM waves?
The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is ______.
Which devices commonly produce microwaves?
