A ray of light is incident normally on a glass slab to thickness 5 cm and refractive index 1.6. The time taken to travel by a ray from source of light to surface of slab is same as to travel through glass slab. The distance of source from the surface is

Step-by-step solution

aligned & T ₁= time taken to reach from source to surface. & s ₁= distance of source from surface. & T ₂= time taken to travel through glass slab & s ₂= distance travelled in slab. T ₁ & = T ₂ & ~s ₁ c = s ₂ v ( Time = Distance/velocity ) & s ₁ c = s ₂ c ( = c / v ) & s ₁= s ₂ =5 1.6=8 ~cm aligned