Question

Glass and water have a refractive index of 1.52 and 1.34 respectively oh, what is the refractive index of glass with respect to water? How much time will light take to pass through a hypothetical tube of 40000 km half filled with water and other half filled with glass?

Answer 1

refractive index of glass with water = refractive index of glass/refractive index of water
= 1.52/1.34 = 1.134

Speed of light in a medium is = c/refractive index
where c is speed of light in vaccum (3x10^8 m/s)

So, time taken = (distance travelled in water / speed of light in water) + (distance travelled in glass / speed of light in glass)
= (20000x10^3 / (c/1.34))+(20000x10^3 / (c/1.52))
put c= 3x10^8
total time = 0.19s