Radiation is a process in which energetic particles or energetic waves travel through a medium or space. The particles or waves radiate (i.e., travel outward in all directions) from a source.

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### How to set up this integral properly?

I'm trying to find the most general expression to compute the total radiant flux (in watts) that a given collector surface $S_{C}$ receives from an emitter surface, $S_E$ (see poorly draw illustration ...
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Beta-ray emitted by a radioactive substance is option A, an electron which was existing outside the nucleus, option B, an electron which was existing inside the nucleus, option C, a pulse of ...
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### How to measure light intensity in a room?

Does anyone know how I would go about measuring the light intensity in a room? I'm not interested in knowing the lux reading, I would like to measure the $W/m^2$ due to thermal radiation in my ...
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### Radiation due to charge particles

We know that accelerated charged particles emits em waves/energy.When we apply voltage across a conductor the electric field applies force on the electrons then why don't the electrons in the ...
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### What force expels the negative charged particle in carbon 14?

What force expels the negative charged particle from carbon 14 as radiation ? Is it electromagnetic force, strong force or weak force ??
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### Why are absorbing bodies hotter over time than reflecting bodies?

I recently learnt about energy transfer by EM Waves and came across the formula for momentum transfer, i.e. Δp = U/c → perfect absorption Δp = 2U/c → perfect reflection then why do absorbing bodies ...
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### Beta decay in Au-198 element

Book "Atoms, radiation, and radiatuon protection" shows decay modes in appendix. In case of Au-198, there is only one type of decay β-. β- : 0.255max (avg 0.079) (1%) 0.961max (avg 0.315) (...
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When fast electrons goes into a target, part of their kinetic energy is converted into electromagnetic radiation, that we call Bremsstrahlung radiation, as they change their velocity. The energy ...
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### Electromagnetic radiation exposure power density per wavelength

Does anyone know a theoretical study or an experimental study of the electromagnetic ambient power density at different wavelengths? To ask simply, how much electromagnetism are human usually exposed ...
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### Why does an alpha particle traveling at the same speed as a beta particle have 'only' about twenty times the energy? Rather than over seven thousand? [closed]

An alpha particle travels at about half the speed as a beta particle, right? ~5% of light speed versus ~10%? Therefore, if you doubled its velocity, its energy would roughly quadruple, correct? (Or ...
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