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प्रश्न
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
पर्याय
Infra-red radiation
X-ray
Microwave
Visible light
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उत्तर
Infra-red radiation
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संबंधित प्रश्न
Why are microwaves considered suitable for radar systems used in aircraft navigation?
How are infrared waves produced?
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1011 Hz belong?
Arrange the following radiations in the order of their increasing wavelength:
X-rays, infrared rays, ratio waves, gamma ray and microwaves.
Give the range of wavelength of the electromagnetic waves visible to us.
Name the region beyond the red end of the spectrum.
Name the radiations of wavelength just longer than 8 × 10-7m.
How are X-rays produced?
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 polarised?
Why is exposure to X-rays injurious to health but not exposure to visible light, when both are electromagnetic waves?
For a given material, the energy and wavelength of characteristic X-rays satisfy
(a) E(Kα) > E(Kβ) > E(Kγ)
(b) E(Mα) > E(Lα) > E(Kα)
(c) λ(Kα) > λ(Kβ) > λ(Kγ)
(d) λ(Mα) > λ(Lα) > λ(Kα).
The stopping potential in a photoelectric experiment is linearly related to the inverse of the wavelength (1/λ) of the light falling on the cathode. The potential difference applied across an X-ray tube is linearly related to the inverse of the cutoff wavelength (1/λ) of the X-ray emitted. Show that the slopes of the lines in the two cases are equal and find its value.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered
X-rays
Name the scientist who discovered Ultraviolet rays
Name three radiations and their wavelength range which are invisible and beyond the violet end of the visible spectrum.
Name the part of the electromagnetic spectrum which is:
Produced by bombarding a metal target with high electrons.
Give one use of electromagnetic radiation in Microwaves.
Answer briefly.
Why are microwaves used in radar?
Answer briefly.
Why high-frequency carrier waves are used for the transmission of audio signals?
A car is moving towards a high cliff. The car driver sounds a horn of frequency f. The reflected sound heard by the driver has a frequency 2f. If v be the velocity of sound, then the velocity of the car, in the same velocity units, will be:
Radio waves of constant amplitude can be generated with.
Electromagnetic waves with wavelength
- λ1 is suitable for radar systems used in aircraft navigation.
- λ2 is used to kill germs in water purifiers.
- λ3 is used to improve visibility in runways during fog and mist conditions.
Identify and name the part of the electromagnetic spectrum to which these radiations belong. Also arrange these wavelengths in ascending order of their magnitude.
Write two uses of the following radiation.
X-rays
Give any two uses of infrared waves.
In an atom X, electrons absorb the energy from an external source. This energy “excites” the electrons from a lower-energy level to a higher-energy level around the nucleus of the atom. When electrons return to the ground state, they emit photons.
The figure below is the energy level diagram of atom X with three energy levels, E1 = 0.00eV, E2 = 1.78eV and E3 = 2.95eV. The ground state is considered 0 eV for reference. The transition of electrons takes place between levels E1 and E2.
- What wavelength of radiation is needed to excite the atom to energy level E2 from E1?
- Suppose the external source has a power of 100 W. What would be the rate of photon emission?
