The focal lengths of a converging lens are f_ | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) According to Cauchy's equation,the refractive index $\mu$ of a material depends on the wavelength $\lambda$ of light,where $\mu$ is inversely prop

Vedclass · Accepted Answer

$f_V < f_R$

Vedclass · Answer

(C) According to Cauchy's equation,the refractive index $\mu$ of a material depends on the wavelength $\lambda$ of light,where $\mu$ is inversely proportional to $\lambda$. Since the wavelength of red light is greater than that of violet light $(\lambda_R > \lambda_V)$,the refractive index for red light is less than that for violet light $(\mu_R Using the lens maker's formula,$\frac{1}{f} = (\mu - 1)(\frac{1}{R_1} - \frac{1}{R_2})$,we see that $\frac{1}{f} \propto (\mu - 1)$.Since $\mu_V > \mu_R$,it follows that $(\mu_V - 1) > (\mu_R - 1)$.Therefore,$\frac{1}{f_V} > \frac{1}{f_R}$,which implies $f_V < f_R$.

The focal lengths of a converging lens are $f_V$ and $f_R$ for violet and red light,respectively. Which of the following relations is correct?

Similar Questions

The radius of curvature for a convex lens is $40 \ cm$ for each surface. Its refractive index is $1.5$. The focal length will be ...... $cm$.

The power of a biconvex lens is $10 \; D$ and the radius of curvature of each surface is $10 \; cm$. The refractive index of the material of the lens is:

The focal length of a converging lens in air is $R$. If it is dipped in water of refractive index $1.33$,then its focal length will be around (Refractive index of lens material is $1.5$).

$A$ thin double convex lens has radii of curvature each of magnitude $40 \; cm$ and is made of glass with refractive index $1.65$. Its focal length is nearly....... $cm$.

$A$ lens made up of different materials forms two images of a point object $O$ as shown in the figure. Then:

Vedclass Test Series

Exam Paper Generator

Online Exam Module