Advertisements
Advertisements
प्रश्न
Answer briefly.
Name the most harmful radiation entering the Earth's atmosphere from outer space.
Advertisements
उत्तर
Name the most harmful radiation entering the Earth's atmosphere from outer space – Ultraviolet radiation
APPEARS IN
संबंधित प्रश्न
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1019 Hz belong?
Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. State the part of the electromagnetic spectrum to which each belongs.
(a) 21 cm (wavelength emitted by atomic hydrogen in interstellar space).
(b) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen; known as Lamb shift).
(c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe].
(d) 5890 Å - 5896 Å [double lines of sodium]
(e) 14.4 keV [energy of a particular transition in 57Fe nucleus associated with a famous high resolution spectroscopic method (Mössbauer spectroscopy)].
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
Name the electromagnetic radiations used for (a) water purification, and (b) eye surgery.
Name three properties of ultraviolet radiations which are similar to visible light.
An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm Calculate the velocity of the wave.
When a Coolidge tube is operated for some time it becomes hot. Where does the heat come from?
Can Lα X-ray of one material have shorter wavelength than Kα X-ray of another?
Can a hydrogen atom emit characteristic X-rays?
The energy of a photon of a characteristic X-ray from a Coolidge tube comes from
If the potential difference applied to the tube is doubled and the separation between the filament and the target is also doubled, the cutoff wavelength
50% of the X-rays coming from a Coolidge tube are able to pass through a 0.1 mm thick aluminium foil. If the potential difference between the target and the filament is increased, the fraction of the X-rays passing through the same foil will be
X-ray incident on a material
(a) exerts a force on it
(b) transfers energy to it
(c) transfers momentum to it
(d) transfers impulse to it.
Heat at the rate of 200 W is produced in an X-ray tube operating at 20 kV. Find the current in the circuit. Assume that only a small fraction of the kinetic energy of electrons is converted into X-rays.
Name the radiation which can be detected by thermopile.
Name the part of the electromagnetic spectrum which is:
Suitable for radar systems used in aircraft navigation.
Define the term "Intensity" in the photon picture of electromagnetic radiation.
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.
Give one use of electromagnetic radiations in Infrared radiation.
Answer briefly.
Can we produce a pure electric or magnetic wave in space? Why?
Solve the numerical problem.
Calculate the frequency in MHz of a radio wave of wavelength 250 m. Remember that the speed of all EM waves in a vacuum is 3.0 × 108 m/s.
Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
Find the photon energy in units of ev for electromagnetic wave if waves length 40 m. Given h = 6.63 × 10–34 J.
What is time period of the light for which the eye is most sensitive?
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.
Electromagnetic waves with wavelength
- λ1 is suitable for radar systems used in aircraft navigation.
- λ2 is used to kill germs in water purifiers.
- λ3 is used to improve visibility in runways during fog and mist conditions.
Identify and name the part of the electromagnetic spectrum to which these radiations belong. Also arrange these wavelengths in ascending order of their magnitude.
Choose the correct option related to wavelengths (λ) of different parts of the electromagnetic spectrum.
