Question

An air bubble is stuck inside a glass ball of refractive index n₁. The surrounding medium outside the glass ball is of refractive index n₂. Each of the ray diagrams given here depict the virtual position of bubble as seen from outside the glass ball. 

In Fig I and II the bubble is nearer to the viewing surface and in Fig III & IV, the bubble is away from the viewing surface. 

 

a. Identify the correct ray diagrams depicting the virtual position of the air bubble as seen from outside the glass ball in each of the following cases. 

i. n₁ > n₂ 

ii. n₁ < n₂ 

b. State true or false:

When viewed from outside: 

i. For n₁ > n₂ and the bubble to the left of C, the apparent position of the bubble is closer to viewing surface. 

ii. For n₁ > n₂ and the bubble is to right of C, the apparent position of the bubble is farther away from viewing surface. 

iii. For n₁ < n₂, and the bubble is to left of C, the apparent position of the bubble is closer to viewing surface. 

iv. For n₁ < n₂, and the bubble is to right of C, the apparent position of the bubble is farther away from viewing surface.

Answer 1

a.

i. n₁ > n₂ : Fig I & Fig III 

ii. n₁ < n₂ : Fig II & Fig IV

b. State true or false 

i. For n₁ > n₂, the apparent position of the bubble is closer to viewing surface in case the bubble is to left of C. TRUE

ii. For n₁ < n₂, the apparent position of the bubble is closer to viewing surface in case the bubble is to right of C. TRUE 

iii. For n₁ > n₂, the apparent position of the bubble is closer to viewing surface in case the bubble is to right of C. FALSE

iv. For n₁ < n₂, the apparent position of the bubble is farther to viewing surface in case the bubble is to left of C. FALSE