A ray of light which is incident in air on the surface of the glass block is deviated through 15 degree. The angle of incidwnce in air is 60 degree.What is the angle of refraction in glass?Also calculate the critical angle for glass air interface.
To find the angle of refraction in glass, we can use Snell's law, which states that the ratio of the sines of the angles of incidence and refraction is equal to the ratio of the velocities of light in the two media.
Snell's law can be written as:
n1 * sin(i) = n2 * sin(r)
Where:
n1 = refractive index of the first medium (air)
n2 = refractive index of the second medium (glass)
i = angle of incidence
r = angle of refraction
Given:
Angle of incidence in air (i) = 60 degrees
Angle of refraction (r) = 15 degrees (deviated)
To find the angle of refraction in glass, we need to determine the refractive index of glass. The refractive index for glass varies depending on the type of glass. Let's assume a typical value of 1.5 for glass.
Using Snell's law, we can calculate the angle of refraction in glass:
n1 * sin(i) = n2 * sin(r)
1 * sin(60) = 1.5 * sin(r)
sin(r) = (1 * sin(60)) / 1.5
sin(r) = 0.866 / 1.5
sin(r) = 0.577
Now, to find the angle of refraction in glass, we can use the inverse sine function (sin^-1):
r = sin^-1(0.577)
r ≈ 35.26 degrees
Therefore, the angle of refraction in glass is approximately 35.26 degrees.
To calculate the critical angle for the glass-air interface, we can use the formula:
critical angle = sin^-1(1 / refractive index)
Given the refractive index of glass (n2) is 1.5,
critical angle = sin^-1(1 / 1.5)
critical angle ≈ sin^-1(0.667)
critical angle ≈ 41.8 degrees
Therefore, the critical angle for the glass-air interface is approximately 41.8 degrees.