Speed of Light Example 1

Jules Bruno
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in this example, it's as to calculate the frequency of the red light emitted by a neon sign with a wavelength of 663.8 nanometers. All right, so we need to determine what our frequency is, which is Mu. They're giving us our wavelength, which is Lambda. Remember, the equation that connects them together is that the speed of light equals them multiplying one another. Now, remember, wavelength needs to be in units off meters. So we need to do a metric prefix conversion where we have 663. nanometers on. We're going to say here that for every one nanometer, it's 10 to the negative 9 m. So here meters will come out to be 6.638 times 10 to the negative 7 m. Now that we have that, we can plug it in. We have the speed of light. We have. We're looking for frequency. We have our wave length in meters, so divide both sides now by meters. Yeah, So when we do that, we're gonna get left at the end. Are seconds inverse. So here we're gonna say frequency equals four point 519 times 10 to the seconds inverse. Because, remember, meters, cancel out here. So we're left with one over seconds, which is the same thing as seconds inverse. Okay, so you're units. Could be either one over seconds or seconds. Inverse or hurts. All of them mean the same thing. And your answer has four sig figs. Because our wavelength was given to us also within four sig figs.