Question

Rays of light are entering from air to water. If the angle of incidence at the surface separating two mediums is 70°, find the angle of refraction of light in water. Absolute refractive index of water is 1.33.

Answer 1

sinA/sinB=1.33

A=70°

sin70°=0.7738

sinB=0.7738/1.33

sinB=0.5818

B=35.57°

Answer 2

Answer:

the angle of refraction is 34.75°

Explanation:

It is given to us that :

The angle of incidence is 70°

So, we know :

$\frac{sin (i)}{sin (r)}$ = r

Here, "r" represents the refractive index

sin i = angle of incidence

sin r = angle of refraction.

Hence, sin 70  = sin (r) x 1.33

or, 0.77 = sin(r) x 1.33

or, 0.77 / 1.33 = sin r

or, 0.57 = sin r

or, r = sin⁻¹ (0.57)

or, r = 34.75°

Therefore, the angle of refraction is 34.75°

Refractive index :

• it is defined as the ratio of the angle of incidence to the angle of refraction of  alight ray that travels from rarer medium to denser medium.

• It is also the ratio of the speed of light in vacuum medium to the speed o light in the second medium which has a greater density.

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