Advertisements
Advertisements
प्रश्न
Name the radiation of the electromagnetic spectrum which is used for the following:
For taking photographs of the sky during the night and foggy conditions . Give the frequency range
Advertisements
उत्तर
Infrared (1011 to 5 × 1014)Hz
APPEARS IN
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 one use of microwaves.
Name three properties of ultraviolet radiations which are similar to visible light.
An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm Calculate the velocity of the wave.
Can X-rays be used for photoelectric effect?
X-ray and visible light travel at the same speed in vacuum. Do they travel at the same speed in glass?
Can Lα X-ray of one material have shorter wavelength than Kα X-ray of another?
The potential difference applied to an X-ray tube is increased. As a result, in the emitted radiation,
(a) the intensity increases
(b) the minimum wavelength increases
(c) the intensity remains unchanged
(d) the minimum wavelength decreases.
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.
