Question

the speed the speed of light in air 3 into 10 power 8 metre per second if the refractive index of Glass is 1.5 find the time taken by light travel a distance of 10 cm in class

Answer 1

Given-
c = 3*10^8 m/s
Refractive index of glass, n = 1.5

Let us first find the speed of light in glass, thus
n = c/v
v = c/n
|Substituting|
v = 3*10^8/1.5
v = 2*10^8 m/s -----> [1]

Now, we know the formulae for finding 'TIME'
Time = Distance/Speed

Here, we need to convert Meter into Centimetre
Be careful while doing it!!

|Substituting|
T = 10cm/2*10^8 m/s x 0.01 (1cm = 0.01 m)
=10cm/0.02*10^8 m/s
=1/0.05*10^8 cm/s
=0.05*10^-8 cm/s (Exponent becomes negative when brought into the numerator
= 5*10^-10 seconds

Hence the time taken for light to travel through 10 cm of glass is 5*10^-10 seconds

Answer 2

Mew (u) =v/c... V = velocity of light in medium, c= velocity of light.. We know that v= d/t.....d=distance, t=time
So, put these vaule in this formula nd solved bro...