Question

A thin hollow prism of refracting angle $3^{°}$, filled with water gives a deviation of $1^{°}$. The refractive index of water is

• A. $1.59$
• B. $1.33$
• C. $1.46$
• D. $1.51$

Answer 1

Answer: (B)

Angle of deviation of the light ray produced by prism is,
$\delta =A(\mu -1)$...(i)
where, $\delta =$ angle of deviation
$A=$ angle of prims and
$\mu =$ refractive index of the prism
Given, $A=3^{\circ },\delta =1^{\circ }$ and $\mu =$ ?
Substituting the given values in Eq. (i), we get
$1^{\circ }=3^{\circ }(\mu -1)\Rightarrow \mu =\frac{4}{3}=1.33$
Hence, the refractive index of the prism is 1.33.