Question

A ray of white light moves through the air and strikes the surface of water in a beaker. The index of refraction of the water is 1.33 and the angle of incidence is 30 degrees. All of the following are true EXCEPT:_________
I. the angle of reflection is 30 degrees
II. the angle of refraction is 30 degrees
III. total internal reflection will result, depending on the critical angle

Answer 1

Answer:

All of the following are true EXCEPT, the angle of refraction is 30 degrees

Explanation:

It is given that,        

The index of refraction of the water is 1.33 and the angle of incidence is 30 degrees. We know that when a ray of white light moves through the air and strikes the surface of water in a beaker, refraction occurs. Let r is the angle of refraction. It can be calculated using Snell's law as :

$n=\dfrac{sin\ i}{sin\ r}$

$sin\ r=\dfrac{sin\ i}{n}$

$sin\ r=\dfrac{sin(30)}{1.33}$

$r=22.08^{\circ}$

So, the angle of refraction is 22.08 degrees.

According to the law of reflection, the angle of incidence is equal to the angle of reflection. Since, it is incident at an angle of 30 degrees, so the angle of reflection will be 30 degrees. Also, total internal reflection will result, depending on the critical angle.

So, the wrong statement is the angle of refraction is 30 degrees. It is equal to 22.08 degrees.