A light ray traveling in glass (n=1.5) strikes the glass-air interface at an ang
Practice Questions
Q1
A light ray traveling in glass (n=1.5) strikes the glass-air interface at an angle of 30°. Will it undergo total internal reflection?
Yes
No
Depends on the angle
Not enough information
Questions & Step-by-Step Solutions
A light ray traveling in glass (n=1.5) strikes the glass-air interface at an angle of 30°. Will it undergo total internal reflection?
Step 1: Identify the refractive index of glass, which is n = 1.5.
Step 2: Determine the angle of incidence, which is given as 30°.
Step 3: Calculate the critical angle (θc) using the formula θc = sin⁻¹(1/n). Here, n = 1.5, so θc = sin⁻¹(1/1.5).
Step 4: Calculate sin(30°), which is 0.5.
Step 5: Calculate θc: sin⁻¹(1/1.5) is approximately 41.8°.
Step 6: Compare sin(30°) with sin(θc). Since 0.5 (sin(30°)) is less than sin(41.8°), the condition for total internal reflection is not met.
Step 7: Conclude that the light ray will not undergo total internal reflection.
Total Internal Reflection – Total internal reflection occurs when a light ray traveling from a denser medium to a less dense medium strikes the interface at an angle greater than the critical angle.
Critical Angle – The critical angle is the angle of incidence above which total internal reflection occurs, calculated using the formula θc = sin⁻¹(n2/n1) where n1 is the refractive index of the denser medium and n2 is that of the less dense medium.
Snell's Law – Snell's Law relates the angles of incidence and refraction to the refractive indices of the two media, given by n1 * sin(θ1) = n2 * sin(θ2).
