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प्रश्न
State two uses of infrared radiations.
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उत्तर
(i) For therapeutic purposes.
(ii) In night photography.
संबंधित प्रश्न
What do you understand by the invisible spectrum?
Is it possible that in a Coolidge tube characteristic Lα X-rays are emitted but not Kα X-rays?
The Kα X-rays of aluminium (Z = 13) and zinc (Z = 30) have wavelengths 887 pm and 146 pm respectively. Use Moseley's law √v = a(Z − b) to find the wavelengths of the Kα X-ray of iron (Z = 26).
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Answer briefly.
What is a carrier wave?
Answer briefly.
Why high-frequency carrier waves are used for the transmission of audio signals?
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
X-rays, gamma rays and microwaves travelling in a vacuum have ______.
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.
What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characteristic of LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb?
Identify the part of the electromagnetic spectrum which:
- produces the heating effect.
- is absorbed by the ozone layer in the atmosphere.
- is used for studying crystal structure.
Write any one method of the production of each of the above radiations.
