Question

the absolute refractive indices of two media A and B are 2.0 and 1.5.if the speed of light in medium B is 2*10 8 m/s calculate the speed of light in: vacum and medium A

Answer 1

speed of light =speed in vacuum/refractive index
2x10^8=speed in vacuum of light/1.5
speed in vacuum of light=3x10^8m/s

now
speed in medium A=speed in vacuum/refractive index
=3x10^8/2=1.5x10^8m/s

Answer 2

Here, nA = 2.0 ; nB = 1.5 ; vB = 2×10 8 m/s

(a) nB = c/vA

So, c = nB × vB = (1.5 × 2× 10 8) m/s

= 3×10 8 m/s

(b) nA = c/vA = (3×10 8/ 2) m/s

= (1.5×10 8) m/s