You get a new pair of sunglasses as a birthday gift from a friend. When wrapping the present, your friend has removed the price tag and all the other labels from the sunglasses. How could you determine whether the pair of shades has polarizing lenses in them or not

Explanation:By using the sunglasses while looking at If your sunglasses are polarized, instead of only seeing the surface of a lake or river, you will suddenly be able to see through the glare and into the water below.

Another one is by comparing two sunglasses, hold your glasses and another one simultaneously and look through both pairs at the same time. Then, rotate one pair of sunglasses about 60 degrees. If both pairs of glasses are polarized, the overlapping area will darken as they filter out excess light. If your pair isn't polarized, however, you won't notice any difference.

Also it can be determined by simple computer test If you rotate your glasses sideways while looking at a computer monitor through polarized glasses, portions of your screen will become blank or go dark. The same also applicable to LCD display screens such as the ones on a gas pump.

this is a good question! i'll do some research and come back when i have the answer!