science

The speed of light in a prticular ype of glass is 1.68x10^8 m/s. What is the index of refraction of the glass? I don't understand if how to solve this problem. Do you put an index of refraction of glass that you know or are you solveing for glass that you don't know? index=speedlightspace/ speedlightinglass where the speed of light in free space is 3x10^8m/s Hey well i just wanted to say that i am having to do this in class but i do not get it if you can plz send me some of your tips of what i can do yhankyou First, if you have a question, it is much better to put it in as a separate post rather than attaching it to a previous question, where is more likely to be overlooked. I am not sure what "this" refers to. If it applies to the original question, just divide the speed of light in space by the speed of light in glass. If not, please state your question in a separate post. I hope this helps. Thanks for asking.