E=hν where E is the energy of a single photon, and ν is the frequency of a single photon. We recall that a photon traveling at the speed of light c and a frequency ν will have a wavelength λ given by λ=cνλ will have an energy given by E=hcλλ=657 nm. This will be E=(6.626×10−34)(2.998×108)(657×10−9)=3.0235×10−19J So we now know the energy of one photon of wavelength 657 nm. To find out how many photons are in a laser pulse of 0.363 Joules, we simply divide the pulse energy by the photon energy or N=Epulse Ephoton=0.3633.0235×10−19=1.2×1018So there would be 1.2×1018 photons of wavelength 657 nm in a pulse of laser light of energy 0.363 Joules.

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3 years ago

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Which two properties are used to define matter?

Fantom [35]

The two properties which are used to define matter are that it has mass and it takes up space. The other properties do not necessarily apply to each matter. Such some matter can be a conductor of heat (such as metal) and some not (such as non metals). Likewise, some matter can be buoyant and float on liquid of density more than it but others would not on the liquids of density less than it. In-fact not all the matters are conductors of energy (such as heat, sound, electricity) or at-least a very poor conductor of energy and tend to find application as insulating agents (non conductors). So the only thing which is necessarily true is that the matter would definitely have mass in even their minutest form as atom and would take up some space.

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3 years ago