A diverging lens with a focal length magnitud | vedclass

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

Question

(B) For the diverging lens,the incident light is parallel,so the image is formed at its focus. Since it is a diverging lens,$f_1 = -25\ cm$.Using the

Vedclass · Accepted Answer

real and at a distance of $40\ cm$ from the converging lens

Vedclass · Answer

(B) For the diverging lens,the incident light is parallel,so the image is formed at its focus. Since it is a diverging lens,$f_1 = -25\ cm$.Using the lens formula $\frac{1}{v_1} - \frac{1}{u_1} = \frac{1}{f_1}$,with $u_1 = \infty$,we get $v_1 = f_1 = -25\ cm$.This image acts as a virtual object for the converging lens. The distance between the lenses is $d = 15\ cm$.The object distance for the converging lens is $u_2 = -(25 + 15) = -40\ cm$.For the converging lens,$f_2 = +20\ cm$. Using the lens formula $\frac{1}{v_2} - \frac{1}{u_2} = \frac{1}{f_2}$:$\frac{1}{v_2} - \frac{1}{-40} = \frac{1}{20}$$\frac{1}{v_2} = \frac{1}{20} - \frac{1}{40} = \frac{2-1}{40} = \frac{1}{40}$$v_2 = +40\ cm$.Since $v_2$ is positive,the final image is real and formed at a distance of $40\ cm$ from the converging lens.

$A$ diverging lens with a focal length magnitude of $25\ cm$ is placed at a distance of $15\ cm$ from a converging lens with a focal length magnitude of $20\ cm$. $A$ beam of parallel light falls on the diverging lens. The final image formed is:

Similar Questions

An achromatic convergent doublet of two lenses in contact has a power $+2 \text{ D}$. The convex lens has power $+5 \text{ D}$. The ratio of the dispersive powers of the convergent and divergent lenses is (in magnitude)

Three lenses of focal lengths $+10 \ cm, -10 \ cm$ and $+30 \ cm$ are placed at distances of $30 \ cm, 35 \ cm$ and $45 \ cm$ respectively from an object. The distance between the object and the final image formed is: (in $cm$)

The focal length of a lens of dispersive power $0.45$ which should be placed in contact with a convex lens of focal length $84 \,cm$ and dispersive power $0.21$ to make the achromatic combination from the two lenses,in $cm$ is

As shown in the figure,a concave lens of focal length $50 \, cm$ and a convex lens of focal length $25 \, cm$ are placed in contact with each other. If a parallel beam of light is incident on the system,how will it emerge?

The plane faces of two identical plano-convex lenses,each with focal length $f$,are pressed against each other using an optical glue to form a convex lens. The distance from the optical centre at which an object must be placed to obtain an image of the same size as the object is

Vedclass Test Series

Exam Paper Generator

Online Exam Module