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प्रश्न
State three properties of ultra-violet radiation similar to visible light.
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उत्तर
(i) Ultra-violet radiations can travel in vacuum as the visible light can do, with the speed 3 × 108 ms−1.
(ii) Both the ultra-violet radiations and the visible light are electromagnetic waves.
(iii) Both the ultra-violet radiations and the visible light obey the laws of reflection and refraction.
संबंधित प्रश्न
Why are microwaves considered suitable for radar systems used in aircraft navigation?
How are infrared waves produced?
What is the range of the wavelength of the following electromagnetic waves?
(a) Ultraviolet
Find the maximum potential difference which may be applied across an X-ray tube with tungsten target without emitting any characteristic K or L X-ray. The energy levels of the tungsten atom with an electron knocked out are as follows.
| Cell containing vacancy | K | L | M |
| Energy in keV | 69.5 | 11.3 | 2.3 |
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.
Give one use of electromagnetic radiation in Ultraviolet radiation.
Microwaves are electromagnetic waves with frequency in the range of.
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.
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?
