The focal length of converging lens is measured for violet, green and red colours. It is respectivel

Question

The focal length of converging lens is measured for violet, green and red colours. It is respectively $f_{v}, f_{g}$, $f_{r}$. We will get\

Professor PC Thomas Classes · Answer

(a): $\frac{1}{f}=(\mu-1)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}ight)$ Since the refractive index of violet colour $\left(\mu_{v}ight)$ is greater than the refractive index of red colour $\left(\mu_{r}ight)$, therefore focal length of violet colour is less than the focal length of red colour or in other words, $f_{v}<f_{r}$.\