Question

refractive indices of water and glass are 4/3 and 3/2 respectively. a ray of light travelling in water is incident on water glass interface at 30 degree. calculate the angle of refraction.

in this question i dont know if we should divide the refrative indices of glass and water. if we shld thn why and should refractive index of glass be in the numertaor or denominaotr? can you please help me out with thi? answer ASAP, tomrw is my test. thankyou.

Answer 1

☆☆heya your answer is here☆☆


In case of refraction. It will follow Snell's law :-
sin i sin r= μglassμwater  ........(1)

put sin i= sin 30o =1/2
put given values in eq (1), we get  :-
(Angle of refraction) r = sin-1(4/9)

Answer 2

Well such a question can be solved by using Snell's Law.

Medium 1 is water.
It's refractive index (n1) is 4/3.

Medium 2 is Glass.
It's refractive index (n2) is 3/2.

So the formula goes as follows

$(n1) \sin(i) = (n2) \sin(r)$
Where i is the angle of incidence and r is the angle of refraction.

Solve this equation.

$\frac{4}{3} \sin(30) = \frac{3}{2} \sin(r) \\ \sin(r) = \frac{4}{3} \times \frac{2}{3} \times \sin(30) \\ \sin(r) = \frac{8}{9} \times \frac{1}{2} \\ \sin(r) = \frac{4}{9}$
r = 26.387799 degrees. (approximately)

You can check the answer since as glass is denser than water, the ray travelling from water to glass goes towards normal hence angle or refraction is less than angle of incidence.

You can solve any of these kind of problems by the above given simple formula.

Hence the Angle of refraction is

26.387799°