Refraction and Lenses Legacy Problem #1 Guided Solution

The speed at which light travels is dependent upon the material through which it is traveling. It travels at a different speed through air, as it does through water, as it does through glass, as it does through diamond. The speed of light within a vacuum, a region of space evacuated of any particles, is 2.998 times 10 to the 8th meters per second. The speed of light in all other materials is less than that value. The actual speed depends upon the properties of the medium, the main property being the optical density of the medium. The best quantitative measure of the optical density of the medium is the index of refraction value. Here, in this question, you are given the speed of light within a vacuum, and you are given the index of refraction value for four different materials. That is the n value that you see listed here. The equation relating the n value to the speed of light through each material is V equal C divided by n, where C is simply the speed of light within a vacuum, and n is the index of refraction, listed here. So to find the answers to these questions, you need to take the speed of light through a vacuum, 2.998 times 10 to the 8th, and you need to divide it by the index of refraction. For water, you divide by 1.333, and when you do, you get an answer of 2.2491 times 10 to the 8th meters per second. You can round that to the fourth significant digit. For crown glass, you do much the same thing, only dividing by 1.52. You get 1.972 times 10 to the 8th meters per second, and you can again round that to the third significant digit. Repeat the process for part C and part D, rounding in part C to the third significant digit to give you 1.39 times 10 to the 8th, and rounding to the fourth significant digit in D to give you a value of 1.239 times 10 to the 8th meters per second.