We can simply plug in the values of , and into the equation and get the respective speeds of glass in different experiments. After that we take the average of them.
The following values are done in radians.
By rearranging the formula, we have:
So we need the value of then take the avrage of this ratio and multiply it by the speed of light in air.
Average: 0.661
Please be aware that this is a ratio which has no units.
0.661 * 299702547 ms-1 = 198063544ms-1
We have the equation , which follows the pattern y = mx. We can plot a graph in order to find the refractive index of glass and at the same time prove Snell’s Law.
Conclusion & Evaluation:
The speed of light in glass is 198063544ms-1. This is found using Snell’s Law, therefore the Snell’s Law is valid.
The refractive index of glass is which is the slope of the graph, 1.51
Percentage error of value:
Highest % error of + smallest % error of + percentage error of
= +
(percentage error of speed of light in air unknown)
= 0.45% + 6.21% = 6.66%
Literature value: 199861638ms-1
Overall percentage error:
|199861638 – 198063544| / 199861638 * 100%
= 0.90%
Our systematic error is expected to be 6.66%, whereas the overall percentage is less than 1%. This means that we did an accurate experiment and avoided some of the systematic error. This might be because we did 7 different sets then taking averages. This will decrease the error within our value.
There are few limitations in this experiment.
