Question

Light goes from medium A to medium B with an angle of incidence at 40* and the angle of refraction at 30*. How will you compare the speed of light in medium B with that in medium A? Explain your answer.

a. The speed of light in B is less than that in A
b. The speed of light in B is the same as that in A
c. The speed of light in B is greater than that in A
d. Any of the above, depending on the specific spectrum

ADVANCE THANK YOU :)

Answer 1

Hello @kennethstudent !

\(\Huge{\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\\\color{white}{.}\\\Huge\color{blue}{\mathfrak{~~~~Welcome~to~OpenStudy!~\ddot\smile}}\\\color{white}{.}\\\\\Huge{\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\)

Answer 2

\(\huge\tt Remember:\)
♦ Whenever a light ray goes from a rarer medium to denser medium then it bends towards the Normal ray.
♦ Whenever a light ray goes from a denser medium to rarer medium then it bends away from the normal ray

Answer 3

Now can u tell me which medium is denser (A or B) ?

Answer 4

a

Answer 5

Incident ray is equal to 40° and refracted ray is equal to 30°. This means the ray shifted its course or bent towards normal after entering to the medium B.

Answer 6

Now read the first point i wrote above

Answer 7

What do you think now ?
Isn't medium B denser ?

Answer 8

Yeah, i think medium a is water and b is air

Answer 9

water is denser than air. So medium a should be air and medium b should be water.

Answer 10

Getting my points?

Answer 11

Yes

Answer 12

Give me a brief explanation to the question

Answer 13

Read this for easy understanding
\(\color{blue}{\text{Originally Posted by}}\) @Abhisar
\(\huge\tt Remember:\)
♦ Whenever a light ray goes from air to water then it bends towards the Normal ray.
♦ Whenever a light ray goes from a water to air then it bends away from the normal ray
\(\color{blue}{\text{End of Quote}}\)

Answer 14

Since refracted ray is smaller than incident ray, medium b must be denser than medium a. Thus velocity of light in medium B is smaller than velocity of light in medium A.

Answer 15

\(\large\tt Note:\)
Velocity of light in denser medium is smaller than velocity of light in rarer medium. For example velocity of light in air is greater than velocity of light in water.

Answer 16

Got it ?

Answer 17

So , A?

Answer 18

Hey give me some reason why light from air travels faster than air

Answer 19

yes it's A

Answer 20

\(\color{blue}{\text{Originally Posted by}}\) @kennethstudent
Hey give me some reason why light from air travels faster than air
\(\color{blue}{\text{End of Quote}}\)

I am not able to understand your question !

Answer 21

tnx!

Answer 22

Do you mean why light travels faster in air than water ?

Answer 23

yes

Answer 24

yeah typo

Answer 25

ok...see actually when i say denser or rarer i mean optically denser (Don't get confused with Density=mass/volume. That is different thing) and optically rarer. Light slows down when it enters an optically denser material and speeds up when it enters optically rarer medium.

You can understand it as analogy with road and traffic. When the traffic is dense we slow down our cars and when traffic is less (or less dense or rare) we speed up our car.