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प्रश्न
What are the ultraviolet rays?
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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.
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संबंधित प्रश्न
Give a reason for the following:
Long-distance radio broadcasts use short-wave bands. Why?
What is the range of the wavelength of the following electromagnetic waves?
(a)X-rays,
What is the range of the wavelength of the following electromagnetic waves?
(a) Ultraviolet
What is the range of the wavelength of the following electromagnetic waves?
(a) Micro waves .
What do you understand by the invisible spectrum?
Give one use of gamma rays.
Name the waves used for taking photographs in dark.
How are X-rays produced?
Which part of electromagnetic spectrum is used in radar systems?
Can X-rays be used for photoelectric effect?
X-ray and visible light travel at the same speed in vacuum. Do they travel at the same speed in glass?
A free atom of iron emits Kα X-rays of energy 6.4 keV. Calculate the recoil kinetic energy of the atom. Mass of an iron atom = 9.3 × 10−26 kg.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Suppose a monochromatic X-ray beam of wavelength 100 pm is sent through a Young's double slit and the interference pattern is observed on a photographic plate placed 40 cm away from the slit. What should be the separation between the slits so that the successive maxima on the screen are separated by a distance of 0.1 mm?
Continuous X-rays are made to strike a tissue paper soaked with polluted water. The incoming X-rays excite the atoms of the sample by knocking out the electrons from the inner shells. Characteristic X-rays are analysed and the intensity is plotted against the wavelength. Assuming that only Kα intensities are detected, list the elements present in the sample from the plot. Use Moseley's equation v − (25 × 1014Hz)(Z − 1)2.
(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 Visible light
Name the scientist who discovered Infra-red waves
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
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 radiation in Ultraviolet radiation.
Give one use of electromagnetic radiations in Infrared radiation.
State two uses of infrared radiations.
X-rays, gamma rays and microwaves travelling in a vacuum have ______.
The area to be covered for T.V telecast is doubled then the height of transmitting antenna (T.V tower) will have to be:-
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- Identify the electromagnetic waves.
- Write one source for each of them.
Given below in the left column are different modes of communication using the kinds of waves given in the right column.
| A. | Optical Fibre Communication |
P. | Ultrasound |
| B. | Radar | Q. | Infrared Light |
| C. | Sonar | R. | Microwaves |
| D. | Mobile Phones | S. | Radio Waves |
From the options given below, find the most appropriate match between entries in the left and the right column.
Which is the correct ascending order of wavelengths?
Photons of an electromagnetic radiation has an energy 11 keV each. To which region of electromagnetic spectrum does it belong?
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.
