Advertisements
Advertisements
प्रश्न
What are the ultraviolet rays?
Advertisements
उत्तर
- Ultraviolet rays can be produced by the mercury-vapor lamp, electric spark, and carbon arc lamp.
- They can also be obtained by striking electrical discharge in hydrogen and xenon gas tubes.
- The Sun is the most important natural source of ultraviolet rays, most of which is absorbed by the ozone layer in the Earth’s atmosphere.
APPEARS IN
संबंधित प्रश्न
What role dose infra-red radiation play in maintain the Earth’s warmth
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1019 Hz belong?
Give a reason for the following:
Long-distance radio broadcasts use short-wave bands. Why?
Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?
Name the phenomenon which shows the quantum nature of electromagnetic radiation.
What do you understand by the statement, "Electromagnetic waves transport momentum"?
Arrange the following radiations in the order of their increasing wavelength:
X-rays, infrared rays, ratio waves, gamma ray and microwaves.
A wave has a wavelength of 10-3 nm. Name the wave.
What is the range of the wavelength of the following electromagnetic waves?
(A) Radio waves.
Name the rays or waves of highest frequency .
Can X-rays be polarised?
If the current in the circuit for heating the filament is increased, the cutoff wavelength
Moseley's Law for characteristic X-ray is √v = a(Z − b). Here,
For a given material, the energy and wavelength of characteristic X-rays satisfy
(a) E(Kα) > E(Kβ) > E(Kγ)
(b) E(Mα) > E(Lα) > E(Kα)
(c) λ(Kα) > λ(Kβ) > λ(Kγ)
(d) λ(Mα) > λ(Lα) > λ(Kα).
What potential difference should be applied across an X-ray tube to get X-ray of wavelength not less than 0.10 nm? What is the maximum energy of a photon of this X-ray in joule?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The energy of a silver atom with a vacancy in K shell is 25.31 keV, in L shell is 3.56 keV and in M shell is 0.530 keV higher than the energy of the atom with no vacancy. Find the frequency of Kα, Kβ and Lα X-rays of silver.
(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.)
An X-ray tube operates at 40 kV. Suppose the electron converts 70% of its energy into a photon at each collision. Find the lowest there wavelengths emitted from the tube. Neglect the energy imparted to the atom with which the electron collides.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered Microwaves
-
- Calculate the speed of the wave.
- Name the medium through which it is traveling.
To which regions of the electromagnetic spectrum do the following wavelengths belong:
(a) 250 nm
(b) 1500 nm
Identify the part of the electromagnetic spectrum used in (i) radar and (ii) eye surgery. Write their frequency range.
State three properties of ultra-violet radiation similar to visible light.
Answer briefly.
Can we produce a pure electric or magnetic wave in space? Why?
Answer briefly.
Give two uses of radio waves.
A radio can tune to any station in the 7.5 mHz to 12 MHz band. What is corresponding wave length band.
Photons of an electromagnetic radiation has an energy 11 keV each. To which region of electromagnetic spectrum does it belong?
Identify the electromagnetic radiation and write its wavelength range, which is used to kill germs in water purified. Name the two sources of these radiations.
Assertion (A): Ultraviolet radiations is scattered more as compared to the microwave radiations.
Reason (R): Wavelength of ultraviolet radiation is more than the wavelength of microwave radiation.
