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प्रश्न
Answer briefly.
Name the most harmful radiation entering the Earth's atmosphere from outer space.
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उत्तर
Name the most harmful radiation entering the Earth's atmosphere from outer space – Ultraviolet radiation
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संबंधित प्रश्न
Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?
The small ozone layer on top of the stratosphere is crucial for human survival. Why?
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
A wave has wavelength 50 Å.
- Name the wave.
- State its speed in vacuum.
- State its one use.
What do you understand by the invisible spectrum?
State the approximate range of wavelength associated with the ultraviolet rays.
State the approximate range of wavelength associated with visible light.
Give one use of gamma rays.
Name the waves produced by the changes in the nucleus of an atom.
Can Lα X-ray of one material have shorter wavelength than Kα X-ray of another?
Can a hydrogen atom emit characteristic X-rays?
If the current in the circuit for heating the filament is increased, the cutoff wavelength
The X-ray beam emerging from an X-ray tube
The figure shows the intensity-wavelength relations of X-rays coming from two different Coolidge tubes. The solid curve represents the relation for the tube A in which the potential difference between the target and the filament is VA and the atomic number of the target material is ZA. These quantities are VB and ZB for the other tube. Then,
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.)
Continuous X-rays are made to strike a tissue paper soaked with polluted water. The incoming X-rays excite the atoms of the sample by knocking out the electrons from the inner shells. Characteristic X-rays are analysed and the intensity is plotted against the wavelength. Assuming that only Kα intensities are detected, list the elements present in the sample from the plot. Use Moseley's equation v − (25 × 1014Hz)(Z − 1)2.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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- Calculate the speed of the wave.
- Name the medium through which it is traveling.
Arrange the following electromagnetic waves in increasing order of their frequencies (i.e. begin with the lowest frequency):
Visible light, y rays, X rays, microwaves, radio waves, infrared radiations, and ultraviolet radiation.
Name two sources of ultraviolet radiation.
State two properties of infrared radiations which differ from visible light.
State three properties of ultra-violet radiation similar to visible light.
Choose the correct option.
How does the frequency of a beam of ultraviolet light change when it travels from air into glass?
Answer briefly.
Why are microwaves used in radar?
Solve the numerical problem.
The speed of light is 3 × 108 m/s. Calculate the frequency of red light of a wavelength of 6.5 × 10−7 m.
Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
An e.m. wave exerts pressure on the surface on which it is incident. Justify.
The fundamental frequency of an open organ pipe is 300 Hz. The first overtone of this pipe has same frequency as first overtone of a closed organ pipe. If speed of sound is 330 m/s, then the length of closed organ pipe is:
Ozone layer above the earth's atmosphere will
If λv, λx and λm Am represents the wavelength of visible light, x-ray and microwaves respectively, then ______.
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 ______.
