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प्रश्न
Answer briefly.
Why are microwaves used in radar?
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उत्तर
Microwaves are used in radar systems for identifying the location of distant objects like ships, airplanes, etc.
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संबंधित प्रश्न
Identify the part of the electromagnetic spectrum which is:
produced by bombarding a metal target by high speed electrons.
Name the parts of the electromagnetic spectrum which is
used to treat muscular strain.
Write in brief, how these waves can be produced.
The small ozone layer on top of the stratosphere is crucial for human survival. Why?
Name the electromagnetic radiations used for (a) water purification, and (b) eye surgery.
Give the range of wavelength of the electromagnetic waves visible to us.
Name the radiations of wavelength just shorter than 4 × 10-7 m.
Name three properties of ultraviolet radiations which are similar to visible light.
Consider a photon of a continuous X-ray coming from a Coolidge tube. Its energy comes from
Frequencies of Kα X-rays of different materials are measured. Which one of the graphs in the figure may represent the relation between the frequency v and the atomic number Z ?
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).
Iron emits Kα X-ray of energy 6.4 keV. Calculate the times taken by an iron Kα photon to cross through a distance of 3 km.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Find the cutoff wavelength for the continuous X-rays coming from an X-ray tube operating at 30 kV.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The short-wavelength limit shifts by 26 pm when the operating voltage in an X-ray tube is increased to 1.5 times the original value. What was the original value of the operating voltage?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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.)
Gamma rays and radio waves travel with the same velocity in free space. Distinguish between them in terms of their origin and the main application.
How will you investigate the existence of the radiation beyond the red and violet extremes of the spectrum?
Name two sources of ultraviolet radiation.
Give one use of electromagnetic radiations in Infrared radiation.
What is the wavelength of the wave whose frequency is 1012 Hz? Name the electromagnetic wave.
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
What are the ultraviolet rays?
Answer briefly.
What are radio waves?
Calculate the wavelength of a microwave of a frequency of 8.0 GHz.
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:
An electron beam is accelerated by a potential difference V to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If λmin is the smallest possible wavelength of X-ray in the spectrum, the variation of log λmin with log V is correctly represented in:
One requires 11eV of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lies in ______.
Electromagnetic waves with wavelength
- λ1 is used in satellite communication.
- λ2 is used to kill germs in water purifies.
- λ3 is used to detect leakage of oil in underground pipelines.
- λ4 is used to improve visibility in runways during fog and mist conditions.
- Identify and name the part of electromagnetic spectrum to which these radiations belong.
- Arrange these wavelengths in ascending order of their magnitude.
- Write one more application of each.
Identify the electromagnetic wave whose wavelength range is from about 10-12 m to about 10-8 m. Write one use of this.
Choose the correct option related to wavelengths (λ) of different parts of the electromagnetic spectrum.
