Question

The diagram alongside shows the refraction of a ray of light from sir to a liquid.
(a) write the values of (i) angle of incidence, (ii) angle of refraction.
(b) use snell’s law to find the refractive index of liquid with respect to air. 

 

Answer 1

(a) Angle of incidence is the angle which the incident ray makes with the normal.
∴ ∠i = 90° − 30° = 60°
(b) Angle of refraction is the angle which the refracted ray makes with the normal.
∴ ∠i = 90° − 45° = 45° 

(b) According to snell’s law.
`"air ^µ liquid"`  = `sin i/sin r=(sin60°)/(sin 45°)`  
Or  `air^µ liquiddd` =`(sqrt3/2)/(1/sqrt2)` 

= `sqrt3/2=1.22`