Assertion and Reason for Total Internal Reflection in Glass Sphere – Rankers Physics

Total Internal Reflection: Practice Problem & Solution

Assertion (A): A solid glass sphere is placed in air. A light ray enters into the sphere from outside. The ray cannot undergo total internal reflection inside the sphere. Reason (R): The angle of incidence at \(\text{1}^ \ext{st}\) surface cannot be greater than the critical angle for air-glass system.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Total Internal Reflection. Understanding the underlying formula is key to arriving at the correct answer below:

A light ray can undergo Total Internal Reflection (TIR) inside a glass sphere if the conditions are met at the glass-air interface. The reason incorrectly relates the critical angle to the first surface incidence and does not explain why TIR could not occur. Both A and R are false.

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