# Answer to Question #24352 in Optics for nagaraju

Question #24352

a ray of light incident at 15 degree on one refracting surface of angle 60 degree suffers deviation 55 degree find angle of emergence

Expert's answer

On the first refraction,

sin (15 deg) = n*sin(60 deg)

It is then deviated by 55 degrees, so it is incident on the output surface at

(60-55) degrees

n*sin(5 deg) = sin(alpha),

where alpha is the sought-for emergence angle.

alpha = arcsin( sin(5 deg) * sin(15 deg) / sin(60 deg) ) = 1.493 degrees.

sin (15 deg) = n*sin(60 deg)

It is then deviated by 55 degrees, so it is incident on the output surface at

(60-55) degrees

n*sin(5 deg) = sin(alpha),

where alpha is the sought-for emergence angle.

alpha = arcsin( sin(5 deg) * sin(15 deg) / sin(60 deg) ) = 1.493 degrees.

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