A beam of light in glass (n=1.5) strikes the glass-air interface at an angle of 60°. Will total internal reflection occur?
Practice Questions
1 question
Q1
A beam of light in glass (n=1.5) strikes the glass-air interface at an angle of 60°. Will total internal reflection occur?
Yes
No
Only if the angle is increased
Only if the angle is decreased
To determine if total internal reflection occurs, we first find the critical angle using sin(θc) = 1/n = 1/1.5, which gives θc ≈ 41.8°. Since 60° > 41.8°, total internal reflection will not occur.
Questions & Step-by-step Solutions
1 item
Q
Q: A beam of light in glass (n=1.5) strikes the glass-air interface at an angle of 60°. Will total internal reflection occur?
Solution: To determine if total internal reflection occurs, we first find the critical angle using sin(θc) = 1/n = 1/1.5, which gives θc ≈ 41.8°. Since 60° > 41.8°, total internal reflection will not occur.
Steps: 8
Step 1: Identify the refractive index of glass, which is given as n = 1.5.
Step 2: Use the formula for the critical angle, which is sin(θc) = 1/n.
Step 3: Substitute the value of n into the formula: sin(θc) = 1/1.5.
Step 4: Calculate 1/1.5, which equals approximately 0.6667.
Step 5: Find the critical angle θc by taking the inverse sine (arcsin) of 0.6667.
Step 6: Calculate θc, which is approximately 41.8°.
Step 7: Compare the angle of incidence (60°) with the critical angle (41.8°).
Step 8: Since 60° is greater than 41.8°, conclude that total internal reflection will not occur.
