Categorize each statement as true or false. At the critical angle, no light is reflected and all light is transmitted. During refraction, the ray that travels through the second medium is called the incident ray. The angle of refraction is measured from the perpendicular to the boundary between two materials. The speed of light in a medium is always less than the speed of light in a vacuum. The virtual image of a pencil in a glass of water is closer to the viewer than the actual pencil. True False

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Part of the text of the exercise is missing.complete text: "a semiconductor laser in a cd player has an output wavelength of 780nm and a power level of 0.10mw. how many photons strike the cd surface during the player of a cd 69 minutes in length? ? "solutionthe power is the energy per unit of time; the laser power is  , and it is applied for a time t of  . from the previous equation we can find the total energy delivered by the laser during this time: then we can find the frequency of the photons of the laser light. in fact, we know the relatioship between c (speed of light), f (frequency) and  (wavelength): using  and  , we getfrom this, we can find the energy carried by one single photon of this frequency: and finally, we can find the number of photons dividing the total energy delivered by the laser by the energy carried by one single photon: