A ray of light passes from air into glass at an angle of incidence of 30 degrees
Practice Questions
Q1
A ray of light passes from air into glass at an angle of incidence of 30 degrees. If the refractive index of glass is 1.5, what is the angle of refraction?
20 degrees
30 degrees
18.4 degrees
22 degrees
Questions & Step-by-Step Solutions
A ray of light passes from air into glass at an angle of incidence of 30 degrees. If the refractive index of glass is 1.5, what is the angle of refraction?
Correct Answer: 18.4 degrees
Step 1: Identify the refractive index of air (n1) and glass (n2). n1 = 1 (for air) and n2 = 1.5 (for glass).
Step 2: Note the angle of incidence (i), which is given as 30 degrees.
Step 3: Write down Snell's law formula: n1 * sin(i) = n2 * sin(r).
Step 4: Substitute the known values into the formula: 1 * sin(30 degrees) = 1.5 * sin(r).
Step 5: Calculate sin(30 degrees), which is 0.5. So the equation becomes: 1 * 0.5 = 1.5 * sin(r).
Step 6: Simplify the equation: 0.5 = 1.5 * sin(r).
Step 7: To find sin(r), divide both sides by 1.5: sin(r) = 0.5 / 1.5.
Step 8: Calculate 0.5 / 1.5, which equals approximately 0.333.
Step 9: Use the inverse sine function to find r: r = sin^(-1)(0.333).
Step 10: Calculate r, which is approximately 18.4 degrees.
Refraction – The bending of light as it passes from one medium to another, described by Snell's law.
Snell's Law – A formula used to calculate the angle of refraction when light passes between two different media.
Refractive Index – A dimensionless number that describes how fast light travels in a medium compared to air.
