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प्रश्न
A wave has wavelength 50 Å.
- Name the wave.
- State its speed in vacuum.
- State its one use.
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उत्तर
- An electromagnetic wave having a wavelength 50 Å is an X-ray. They have a wavelength in the range of 0.1 Å to 100 Å.
- The speed of an electromagnetic wave (here X-ray) in a vacuum is 3x108 m/s.
- Since, they are stopped by bones, they are used for the detection of fractures in bones, teeth, etc., and for diagnostic purposes such as CAT scans in medical science.
संबंधित प्रश्न
(a) Give a list of at least five radiations, in order of their increasing frequencies, which make up the complete electromagnetic spectrum.
(b) Which of the radiation mentioned by you in part (a) has the highest penetrating power.
Name the radiations of wavelength just longer than 8 × 10-7m.
Name two sources, each of infrared radiations and ultraviolet radiations.
Consider a photon of a continuous X-ray coming from a Coolidge tube. Its energy comes from
The X-ray beam emerging from an X-ray tube
Visible light passing through a circular hole forms a diffraction disc of radius 0.1 mm on a screen. If an X-ray is passed through the same setup, the radius of the diffraction disc will be
The distance between the cathode (filament) and the target in an X-ray tube is 1.5 m. If the cutoff wavelength is 30 pm, find the electric field between the cathode and the target.
(Use Planck constant h = 6.63 × 10-34 Js= 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.)
What are the ultraviolet rays?
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?
