Answer:
Photoelectric effect, pair production and Compton scattering
Explanation:
Gamma rays, having no charge, can be slowed slowly by ionization as a material passes through. They suffer other mechanisms that eventually make them disappear, transferring their energy, they can cross several centimeters of a solid, or hundreds of meters of air, without undergoing any process or affecting the material they cross. Then they suffer one of the three effects and deposit much of their energy there. The three mechanisms of interaction with matter are: the photoelectric effect, the Compton effect and the production of pairs.
The photoelectric effect is that the photon meets an electron in the material and transfers all its energy, disappearing the original photon. The secondary electron acquires all the energy of the photon in the form of kinetic energy, and is sufficient to separate it from its atom and convert it into a projectile. This is stopped by ionization and excitation of the material
In the Compton effect the photon collides with an electron as if it were a clash between two elastic spheres. The secondary electron acquires only part of the energy of the photon and the rest takes it with another photon of lesser energy and diverted.
When an energy photon approaches the intense electric field of a nucleus, the production of pairs can happen. In this case the photon is transformed into an electron positron pair. Since the sum of the mass of the pair is 1.02 MeV, it cannot happen if the photon's energy is less than this amount. If the energy of the original photon is greater than 1.02 MeV, the surplus is distributed by the electron and the positron as kinetic energy, and the material can be ionized. The positron at the end of its path forms a positronium and then annihilates producing two annihilation photons, 0.51 MeV each.
Convection
Explanation:
Heat is a form of thermal energy borne as result of thermal energy. It is observed as temperature differences between places.
There are different types of heat transfer:
- Conduction
- Convection
- Radiation
Conduction is a heat transfer which involves the actual movement of the collision of the molecules of the medium.
Convection is a heat transfer in fluids by their movement from areas of higher to places of lower heat.
Radiation is heat transfer using electromagnetism and does not involve molecules of the medium
The process of heat transfer from ground to the air touching it is convection. It involves particles of the air.
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Convection brainly.com/question/1140127
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Answer:
Speed, v = 5 m/s
Explanation:
The length of the football field, l = 100 m
the person takes 20 seconds to run its length
v=
t
d
v=
20 s
100 m
v=5 m/s
