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प्रश्न
Choose the correct option.
Earth’s atmosphere is richest in
विकल्प
UV
IR
X-ray
Microwaves
उत्तर
Earth’s atmosphere is richest in IR
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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?
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
The wavelengths for the light of red and blue colours are roughly 7.8 × `10^7` m and 4.8 × `10^7` m respectively.
(a) Which colour has the greater speed in vacuum?
(b) Which colour has the greater speed in glass?
What is the range of the wavelength of the following electromagnetic waves?
(a) Visible.
State the approximate range of wavelength associated with the ultraviolet rays.
Name the radiations of wavelength just longer than 8 × 10-7m.
When a Coolidge tube is operated for some time it becomes hot. Where does the heat come from?
If the current in the circuit for heating the filament is increased, the cutoff wavelength
For harder X-rays,
(a) the wavelength is higher
(b) the intensity is higher
(c) the frequency is higher
(d) the photon energy is higher.
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.
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?
Heat at the rate of 200 W is produced in an X-ray tube operating at 20 kV. Find the current in the circuit. Assume that only a small fraction of the kinetic energy of electrons is converted into X-rays.
The Kα and Kβ X-rays of molybdenum have wavelengths 0.71 A and 0.63 A respectively. Find the wavelength of Lα X-ray of molybdenum.
Name the scientist who discovered radio waves
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
How will you investigate the existence of the radiation beyond the red and violet extremes of the spectrum?
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
Choose the correct option.
How does the frequency of a beam of ultraviolet light change when it travels from air into glass?
Answer briefly.
Why are microwaves used in radar?
Answer briefly.
Does an ordinary electric lamp emit EM waves?
Solve the numerical problem.
The speed of light is 3 × 108 m/s. Calculate the frequency of red light of a wavelength of 6.5 × 10−7 m.
SONAR emits which of the following waves?
The electric field intensity produced by the radiations coming from 100 W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50 W bulb at the same distance is ______.
Which one of the following electromagnetic radiation has the least wavelength?
