Question

An air bubble in a glass slab $(\mu =1.5)$ is 6 cm deep when viewed from one face and 4 cm deep when viewed from the opposite face. The thickness of the glass plate is3

• A. 10 cm
• B. 6.67 cm
• C. 15 cm
• D. None of these

Answer 1

The correct option is C

15 cm

Let thickness of slab be t and distance of air bubble from one side is x
When viewed from side (1) : $1.5=\frac{x}{6}\Rightarrow x=9cm$
When viewed from side (2) : $1.5=\frac{(t-x)}{4}\Rightarrow 1.5=\frac{(t-9)}{4}\Rightarrow t=15cm$