# what is the critical angle for light traveling from crown glass (n = 1.52) into water (n = 1.33)?

## Question

What is the critical angle for light traveling from crown glass (n = 1.52) into water (n = 1.33)?

The final answer to the above question is that the critical angle is 61 degrees (610)

### Proof

Here is the method I applied to solve the problem:

Data

We will identify our data from the above question

The light travels from crown glass = Incident Light = ni = 1.52

It then passes through water = Refracted ray of light = nr = 1.33

According to the definition of the critical angle. When light passes through a denser to a less dense medium, it forms an angle of 900. Therefore, the angle of refraction, θr = 900

Unknown

The critical angle, θi = ?

Formula

We will apply the formula

nisinθi = nrsinθr

#### Solution

Hence, insert the data into the formula

1.52 x sinθi = 1.33 sin900

Divide both sides by 1.52 to obtain

sinθi = (1.33 x sin900) / 1.52 = (1.33 x 1) / 1.52 = 1.33 / 1.52 = 0.875

Hence, sinθi = 0.875

We will make θi subject of the formula

θi = sin-1 0.875 = 61.044980

Therefore, the critical angle θi is 61 degrees.

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light.physics