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प्रश्न
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
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उत्तर
In the absence of an atmosphere, there would be no greenhouse effect on the surface of the Earth. As a result, the temperature of the Earth would decrease rapidly, making it chilly and difficult for humans to survive.
संबंधित प्रश्न
How are infrared waves produced?
The terminology of different parts of the electromagnetic spectrum is given in the text. Use the formula E = hv (for energy of a quantum of radiation: photon) and obtain the photon energy in units of eV for different parts of the electromagnetic spectrum. In what way are the different scales of photon energies that you obtain related to the sources of electromagnetic radiation?
Give a reason for the following:
It is necessary to use satellites for long-distance TV transmission. Why?
Give one use of gamma rays.
In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?
Can X-rays be used for photoelectric effect?
Can a hydrogen atom emit characteristic X-rays?
Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
(a) target material
(b) accelerating voltage
(c) separation between the target and the filament
(d) temperature of the filament.
The electron beam in a colour TV is accelerated through 32 kV and then strikes the screen. What is the wavelength of the most energetic X-ray photon?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
A free atom of iron emits Kα X-rays of energy 6.4 keV. Calculate the recoil kinetic energy of the atom. Mass of an iron atom = 9.3 × 10−26 kg.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Two waves A and B have wavelength 0.01 Å and 9000 Å respectively.
Name the two waves. compare the speeds of these waves when they travel in vacuum.
Name the part of the electromagnetic spectrum which is:
Produced by bombarding a metal target with high electrons.
Name the radiation of the electromagnetic spectrum which is used for the following:
To photograph internal parts of the human body and Give the frequency range
Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
The magnetic field of a beam emerging from a filter facing a floodlight is given by B0 = 12 × 10–8 sin (1.20 × 107z – 3.60 × 1015t) T. What is the average intensity of the beam?
Write two uses of the following radiation.
Gamma rays
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.
Given below in the left column are different modes of communication using the kinds of waves given in the right column.
| A. | Optical Fibre Communication |
P. | Ultrasound |
| B. | Radar | Q. | Infrared Light |
| C. | Sonar | R. | Microwaves |
| D. | Mobile Phones | S. | Radio Waves |
From the options given below, find the most appropriate match between entries in the left and the right column.
Name two electromagnetic waves of wavelength smaller than that of violet light.
