A parallel beam of light is incident on a sys | vedclass

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

Question

(B) For a parallel beam of light to emerge from a system of two convex lenses,the intermediate image formed by the first lens must coincide with the f

Vedclass · Accepted Answer

$30$

Vedclass · Answer

(B) For a parallel beam of light to emerge from a system of two convex lenses,the intermediate image formed by the first lens must coincide with the focal point of the second lens.$1$. The first lens $L_1$ with focal length $f_1 = 20 \, cm$ receives parallel rays,so it forms an image at its focal point,at a distance of $20 \, cm$ from $L_1$.$2$. This image acts as an object for the second lens $L_2$ with focal length $f_2 = 10 \, cm$. For the rays to emerge parallel from $L_2$,this object must be placed at the focal point of $L_2$.$3$. Therefore,the distance between the two lenses $d$ must be the sum of their focal lengths:$d = f_1 + f_2 = 20 \, cm + 10 \, cm = 30 \, cm$.Thus,the correct distance is $30 \, cm$.

$A$ parallel beam of light is incident on a system of two convex lenses with focal lengths $f_1 = 20 \, cm$ and $f_2 = 10 \, cm$. What should be the distance between the two lenses so that the rays,after refraction from both lenses,emerge as a parallel beam? (in $cm$)

Similar Questions

Two lenses of power $-15 \ D$ and $+5 \ D$ are in contact with each other. The focal length of the combination is ....... $cm$.

An eye specialist prescribes spectacles having a combination of a convex lens of focal length $40\, cm$ in contact with a concave lens of focal length $25\, cm$. The power of this lens combination in diopters is

Two lenses of power $+10D$ and $-5D$ are placed in contact. At what distance (in $cm$) should an object be held from the lens combination to obtain a virtual image of magnification $2$?

Two lenses having focal lengths in the ratio $f_1:f_2 = 2:3$ are combined to produce no net dispersion. Find the ratio of the dispersive powers of the glasses used.

Two thin lenses have a combined power of $+9 \text{ D}$. When they are separated by a distance of $20 \text{ cm}$,their equivalent power becomes $+\frac{27}{5} \text{ D}$. Their individual powers (in dioptre) are

Vedclass Test Series

Exam Paper Generator

Online Exam Module