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प्रश्न
What happens when an electron collides with a positron?
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उत्तर
They annihilate each other, producing gamma ray photons.
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)].
State the approximate range of wavelength associated with the ultraviolet rays.
Find the energy, the frequency and the momentum of an X-ray photon of wavelength 0.10 nm.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered
X-rays
Name any two electromagnetic waves which have a frequency higher than that of violet light. State one use of each.
State two uses of infrared radiations.
Following QN ∴ 14, the radiation force on the roof will be
The frequency of e. m waves which is best suited .to observed of radius 3 × 10–4 his of the order of
What is called the invisible spectrum?
How do the wavelengths and frequencies of microwaves compare with those of radio waves?
