Page 16 - Science E-Book Prep.3 2024-2025 1st term_ unit 2_Neat

Science Department
Prep.3

The focus of the convex lens(converging):
The incident rays through the convex lens are collected in one point
(the focus of the lens (F)

How to determine the focus and the focal length of the convexlens?

Steps Observation
Parallel rays will fall on the lens.
Fix the lens and let a distant
light source (as sun) facing Refracted rays are collected in one
oneof its faces lit point (the focus of the lens)
that can be received on the screen.
Move the screen closer
andfarther until you get 34
the lit point

Measure the
distancebetween the
lit point
and the optical center of the
lens (focal length)

First Term