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
Give a reason for the following:
It is necessary to use satellites for long-distance TV transmission. Why?
Consider a photon of a continuous X-ray coming from a Coolidge tube. Its energy comes from
Find the maximum potential difference which may be applied across an X-ray tube with tungsten target without emitting any characteristic K or L X-ray. The energy levels of the tungsten atom with an electron knocked out are as follows.
| Cell containing vacancy | K | L | M |
| Energy in keV | 69.5 | 11.3 | 2.3 |
Name the scientist who discovered Visible light
Name the scientist who discovered radio waves
State the name and the range of wavelength of the invisible electromagnetic waves beyond the red end of the visible spectrum.
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
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.
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:
Name one radiation having the wavelength longer than the wavelength of these radiations.
