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प्रश्न
What role dose infra-red radiation play in physical therapy?
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उत्तर
The molecules of CO₂, NH₃ and water which are present in most materials absorb infrared waves. Due to this, the molecules heat and heat their surroundings. Hence, their thermal motion increases. Medical instruments, such as the infrared lamp which is used in physiotherapy, work on this principle.
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संबंधित प्रश्न
The wavelengths for the light of red and blue colours are roughly 7.8 × `10^7` m and 4.8 × `10^7` m respectively.
(a) Which colour has the greater speed in vacuum?
(b) Which colour has the greater speed in glass?
What is the range of the wavelength of the following electromagnetic waves?
(a) Gamma rays.
Name the waves produced by the changes in the nucleus of an atom.
Characteristic X-rays may be used to identify the element from which they are being emitted. Can continuous X-rays be used for this purpose?
Consider a photon of continuous X-ray and a photon of characteristic X-ray of the same wavelength. Which of the following is/are different for the two photons?
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.)
State two properties of infrared radiations which differ from visible light.
What is time period of the light for which the eye is most sensitive?
Where does infrared radiation lie relative to visible light?
How does the frequency of infrared radiation compare with that of microwaves?
