Question

A straight rod is partially immersed in water $(\mu =1.33)$. Its submerged portion appears to be inclined at ${45}^o$ with the surface when viewed vertically from air. The actual inclination of the rod is?

• A. ${32.14}^o$
• B. ${45}^o$
• C. ${57.9}^o$
• D. ${62}^o$

Answer 1

The correct option is C ${57.9}^o$

Given: A straight rod is partially immersed in water ($\mu =1.33$). Its submerged portion appears to be inclined at ${45}^o$ with the surface when viewed vertically from air.

To find the actual inclination of the rod

Solution:

We know,

$\mu =\frac{\sin i}{\sin r}⟹1.33=\frac{\sin \left(45\right)}{\sin r}⟹\sin r=\frac{\frac{1}{\sqrt{2}}}{1.33}⟹r={\sin }^{-1}\left(0.53\right)={32.11}^{\circ }$

Is the angleof refraction.

So the actual inclination is $90-r=90-32.11={57.9}^{\circ }$