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प्रश्न
Define the term "Intensity" in the photon picture of electromagnetic radiation.
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उत्तर
The intensity I is defined as the total amount of energy falling on a given surface/Region per unit time 'rand per unit area A:
If the total energy emitted = nhv
Then, I = `(nhν)/(At)`
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संबंधित प्रश्न
Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. State the part of the electromagnetic spectrum to which each belongs.
(a) 21 cm (wavelength emitted by atomic hydrogen in interstellar space).
(b) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen; known as Lamb shift).
(c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe].
(d) 5890 Å - 5896 Å [double lines of sodium]
(e) 14.4 keV [energy of a particular transition in 57Fe nucleus associated with a famous high resolution spectroscopic method (Mössbauer spectroscopy)].
What is the range of the wavelength of the following electromagnetic waves?
(a) Infrared.
What are ultraviolet radiations?
In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?
One of the following wavelengths is absent and the rest are present in the X-rays coming from a Coolidge tube. Which one is the absent wavelength?
How will you investigate the existence of the radiation beyond the red and violet extremes of the spectrum?
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
Find the photon energy in units of ev for electromagnetic wave if waves length 40 m. Given h = 6.63 × 10–34 J.
Write two uses of the following radiation.
X-rays
Name one radiation having the wavelength longer than the wavelength of these radiations.
