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प्रश्न
What is ‘Pair production’?
Answer the following question briefly and to the point:
What is Pair production?
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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
Show that the density of nucleus over a wide range of nuclei is constant-independent of mass number A.
Two nuclei have mass numbers in the ratio 1: 2. What is the ratio of their nuclear densities?
If neutrons exert only attractive force, why don't we have a nucleus containing neutrons alone?
What is a neutrino?
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:
Deuteron is a bound state of a neutron and a proton with a binding energy B = 2.2 MeV. A γ-ray of energy E is aimed at a deuteron nucleus to try to break it into a (neutron + proton) such that the n and p move in the direction of the incident γ-ray. If E = B, show that this cannot happen. Hence calculate how much bigger than B must E be for such a process to happen.
Mass numbers of two nuclei are in the ratio of 4 : 3. Their nuclear densities will be in the ratio of ______.
Which of the following are the constituents of the nucleus?
Experiments on the scattering of alpha particles showed that the radius of a nucleus is smaller than the radius of an atom by a factor of about:
The atomic mass unit (u) is defined as:
