Advertisements
Advertisements
प्रश्न
Answer briefly.
Give two uses of ultraviolet rays.
Advertisements
उत्तर
Uses:
- Ultraviolet rays destroy germs and bacteria and hence they are used for sterilizing surgical instruments and for purification of water.
- Used in burglar alarms and security systems.
- Used to distinguish real and fake gems.
APPEARS IN
संबंधित प्रश्न
Use the formula λm T= 0.29 cm K to obtain the characteristic temperature ranges for different parts of the electromagnetic spectrum. What do the numbers that you obtain tell you?
Give a reason for the following:
Long-distance radio broadcasts use short-wave bands. Why?
State an additional use of the X-rays waves
State Moseley's law
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.
Name the radiations of wavelength just longer than 8 × 10-7m.
How are X-rays produced?
Why is exposure to X-rays injurious to health but not exposure to visible light, when both are electromagnetic waves?
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
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 electric current in an X-ray tube (from the target to the filament) operating at 40 kV is 10 mA. Assume that on an average, 1% of the total kinetic energy of the electron hitting hte target are converted into X-rays.
(a) What is the total power emitted as X-rays and (b) how much heat is produced in the target every second?
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.
The Kα and Kβ X-rays of molybdenum have wavelengths 0.71 A and 0.63 A respectively. Find the wavelength of Lα X-ray of molybdenum.
If the operating potential in an X-ray tube is increased by 1%, by what percentage does the cutoff wavelength decrease?
(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.)
Calculate the shortest wavelength of electromagnetic radiation present in Balmer series of hydrogen spectrum.
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.
Name the radiations used for the detection of fracture in bones.
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.
Microwaves are electromagnetic waves with frequency in the range of.
The frequency of x-rays, y-rays and ultraviolet rays are respectively a, b and c. Then:-
Radio waves of constant amplitude can be generated with.
Write two uses of the following radiation.
X-rays
Write two uses of the following radiation.
Gamma rays
Photons of an electromagnetic radiation has an energy 11 keV each. To which region of electromagnetic spectrum does it belong?
What is the wavelength range of electromagnetic radiation used in radio broadcast?
Name two electromagnetic waves of wavelength smaller than that of violet light.
