SATHEE: Optics Question 442

Optics Question 442

Question: The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image

Options:

A) 1.25 cm

B) 2.5 cm

C) 1.05 cm

D) 2 cm

Show Answer

Answer:

Correct Answer: B

Solution:

[b] Convex lens will form image $I_{1}$ at its focus which acts like a virtual object for concave lens.

Hence, for concave lens, $u = + 4 c m$ , $f = 20$ cm.

So by lens formula $\frac{1}{- 20} = \frac{1}{v} - \frac{1}{4} \Rightarrow v = 5 c m$ i.e., distance of final image $(I_{2})$ from concave lens v=5 cm by using $\frac{v}{u} = \frac{I}{O} \Rightarrow \frac{5}{4} = \frac{I}{2} \Rightarrow (I_{2}) = 2.5 c m$

Play Store

App Store

Ask SATHEE

Welcome to SATHEE !
Select from 'Menu' to explore our services, or ask SATHEE to get started. Let's embark on this journey of growth together! 🌐📚🚀🎓

I'm relatively new and can sometimes make mistakes.
If you notice any error, such as an incorrect solution, please use the thumbs down icon to aid my learning.
To begin your journey now, click on "I understand".

Optics Question 442

Question: The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Menu