Advertisements
Advertisements
प्रश्न
What is ‘Pair production’?
Answer the following question briefly and to the point:
What is Pair production?
Advertisements
उत्तर १
An electron and a positron are produced when an intense γ-ray photon strikes a heavy material. One of the substance’s nuclei is responsible for absorbing the photon. Pair creation is the term used to describe this process of energy being transformed into mass.
Equation: \[\ce{\underset{(γ-Photon)}{γ} = \underset{(Electron)}{_-1β^0} + \underset{(Positron)}{_+1β^0}}\]
उत्तर २
In a semiconductor, when a covalent bond is broken, the electron comes out, leaving behind a hole (deficiency of electrons). Thus, an electron-hole pair is formed by rupturing a covalent bond.
उत्तर ३
A positron pair from a gamma ray (or radiation) photon passes close to an atomic nucleus.
संबंधित प्रश्न
In the study of Geiger-Marsdon experiment on scattering of α particles by a thin foil of gold, draw the trajectory of α-particles in the coulomb field of target nucleus. Explain briefly how one gets the information on the size of the nucleus from this study.
From the relation R = R0 A1/3, where R0 is constant and A is the mass number of the nucleus, show that nuclear matter density is independent of A
Find the Q-value and the kinetic energy of the emitted α-particle in the α-decay of `""_88^226 "Ra"`.
Given `"m"(""_88^226"Ra")` = 226.02540 u, `"m"(""_86^222 "Rn")` = 222.01750 u,
`"m"(""_86^220 "Rn")`= 220.01137 u, `"m"(""_84^216 "Po")`= 216.00189 u.
The nucleus `""_10^23"Ne"` decays by `beta^(-)`emission. Write down the β decay equation and determine the maximum kinetic energy of the electrons emitted. Given that:
`"m"(""_10^23 "Ne")` = 22.994466 u
`"m"(""_11^23 "Na")` = 22.989770 u.
Two nuclei have mass numbers in the ratio 1: 2. What is the ratio of their nuclear densities?
The nuclei of isotopes of a given element contain the same number of ______.
Two cars of mass m1 and m2 are moving in circles of radii r1 and r2, respectively. Their speeds are such that they make complete circles at the same time t. The ratio of their centripetal acceleration is:
A nucleus with mass number 240 breaks into two fragments each of mass number 120, the binding energy per nucleon of unfragmented nuclei is 7.6 MeV while that of fragments is 8.5 MeV. The total gain in the binding energy in the process is:
All nuclides with the same mass number are called:
Using the isotopic masses 34.98 u (75.4% abundance) and 36.98 u (24.6% abundance), the average atomic mass of chlorine is approximately:
The number of protons in the nucleus is equal to:
