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Question
Give one use of gamma rays.
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Solution
Gamma rays are used in medical science to kill cancer cells.
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RELATED QUESTIONS
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)].
(a) Give a list of at least five radiations, in order of their increasing frequencies, which make up the complete electromagnetic spectrum.
(b) Which of the radiation mentioned by you in part (a) has the highest penetrating power.
Name the waves of wavelength nearly 0.1 nm.
Name two sources, each of infrared radiations and ultraviolet radiations.
What are ultraviolet radiations?
The energy of a silver atom with a vacancy in K shell is 25.31 keV, in L shell is 3.56 keV and in M shell is 0.530 keV higher than the energy of the atom with no vacancy. Find the frequency of Kα, Kβ and Lα X-rays of silver.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
How will you investigate the existence of the radiation beyond the red and violet extremes of the spectrum?
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.
An electron beam is accelerated by a potential difference V to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If λmin is the smallest possible wavelength of X-ray in the spectrum, the variation of log λmin with log V is correctly represented in:
Electromagnetic waves of wavelengths λ1, λ2 and λ3 are used in a radar system, in water purifiers and in remote switches of TV, respectively.
- Identify the electromagnetic waves.
- Write one source for each of them.
