Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
3.7k views
in JEE by (15 points)
edited by

What is the position of equivalent lens in a lens combination separated by a distance having focal lengths f1 And f2

Please log in or register to answer this question.

1 Answer

0 votes
by (1.7k points)

image

Let a point object O is placed on the principal axis 
By lens formula for image formation by lens L1​
v′1​−u1​=f1​1​          ....... (1)
I' serves as a virtual object for the second lens L2​ which forms a final image I at a distance 'v'. Then for L2​
v1​−v′1​=f2​1​         ........ (2)
Adding equation (1) and (2)
v1​−u1​=f1​1​+f2​1​      .......... (3)
If we replace these two lenses by a single lens such that if an object is kept at u image is formed at v then its focal length f is given by
v1​−u1​=f1​       ....... (4)
From equation (3) and (4) we get
f1​=f1​1​+f2​1​

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...