Is this true?

Question

when a straw is seen in the air ( as you see it normally, outside of water or liquid) it seems normal because light travelling from the straw is at normal speed . but when placed in water the speed of light travelling in water is decreased because water is denser than air

Answer 1

Yes, this is basically true.

Of course, it ISN'T a property of the STRAW! It's true for ANYTHING immersed in either air or water, or seen through them. It's a property of the MEDIUM through which light is travelling.

Light travels in a perfect vacuum at a well-known uniform velocity, known as ' c.' But light consists of electromagnetic fields, with changing electric and magnetic fields chasing one another at a well-specified velocity that is characteristic of (i) the empty space, or (ii) the medium, through which it's moving.

A physical medium is made up of atoms and molecules, which ultimately means things like protons, neutrons and electrons. When the e.m. waves travel through the medium, they "jiggle" the electrons, which are very light and so more easily moved. The jiggling electrons in turn give rise to their own e.m. fields which have a "back-reaction" on the original waves. (This is a physical equivalent of Le Chatalier's Principle in chemistry --- disturbed equilibria always react in such a way as to OPPOSE the imposed changes.)

As a result, light's e.m. waves move slower through a realistic medium, and in a broad way, the more electrons they encounter per unit volume, the more the light is slowed down. Since a DENSER medium will in general have more electrons per unit volume, THAT'S why light generally travels slower in denser media.

Live long and prosper.

Answer 2

Water causes light to refract. If you put a long straw in a tall glass, fill it half way with water, look at if from the side. The straw below the water won't line up with the straw above the water.

Answer 3

yes,the speed of light in water is less in water than in airby a factor mi=1.3 ,the refractive index of water with respect to air. the light suffers refraction when it passes fro water to air and this leads to straw or any other immersed object look bent.

Answer 4

Yes, if you place the straw in the water, you would notice that it would not look straight. This is because water bends light.

Answer 5

Yep

Answer 6

True