C.... 376 tbh just took the test and was right
<span>E=hν</span> 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 <span>λ=<span>cν</span></span>λ will have an energy given by <span>E=<span><span>hc</span>λ</span></span><span>λ=657</span> nm. This will be <span>E=<span><span>(6.626×<span>10<span>−34</span></span>)(2.998×<span>108</span>)</span><span>(657×<span>10<span>−9</span></span>)</span></span>=3.0235×<span>10<span>−19</span></span>J</span>
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 <span>N=<span><span>E<span>pulse </span></span><span>E<span>photon</span></span></span>=<span>0.363<span>3.0235×<span>10<span>−19</span></span></span></span>=1.2×<span>1018</span></span>So there would be <span>1.2×<span>1018</span></span><span> photons of wavelength 657 nm in a pulse of laser light of energy 0.363 Joules.</span>
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.