Advertisements
Advertisements
प्रश्न
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.
Advertisements
उत्तर
Radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, gamma rays, and cosmic rays provide the whole range (electromagnetic spectrum) in increasing frequency and decreasing wavelength order. The type of radiation and their frequency and wavelength ranges are as follows:
| Types of Radiation | Frequency Range (Hz) | Wavelength Range |
| Gamma-rays | 1020 - 1024 | < 10-12 m |
| X-rays | 1017 - 1020 | 1 nm - 1 pm |
| Ultraviolet | 1015 - 1017 | 400 nm - 1 nm |
| Visible | 4 × 1014 - 7.5 × 1014 | 750 nm - 400 nm |
| Near-infrared | 1 × 1014 - 4 × 1014 | 2.5 µm - 750 nm |
| Infrared | 1013 - 1014 | 25 µm - 2.5 µm |
| Microwaves | 3 × 1011 - 1013 | 1 mm - 25 µm |
| Radio waves | < 3 × 1011 | > 1 mm |
In water purifiers, ultraviolet light is utilised to kill bacteria. The sun is the most powerful source of UV radiation.
UV lamps, arc welding, and mercury vapour lamps are examples of man-made ultraviolet sources. Carbon, Xenon, and other arcs are some of the devices that release UV radiation.
APPEARS IN
संबंधित प्रश्न
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1011 Hz belong?
Give one use of gamma rays.
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?
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.)
Name three radiations and their wavelength range which are invisible and beyond the violet end of the visible spectrum.
Name the radiation of the electromagnetic spectrum which is used for the following:
To photograph internal parts of the human body and Give the frequency range
Choose the correct option.
Earth’s atmosphere is richest in
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.
A car is moving towards a high cliff. The car driver sounds a horn of frequency f. The reflected sound heard by the driver has a frequency 2f. If v be the velocity of sound, then the velocity of the car, in the same velocity units, will be:
Following QN ∴ 14, the radiation force on the roof will be
