Question

A sharp image of a distant object is obtained on a screen using a convex lens. In order
to determine the focal length of a lens, a student needs to measure the distance between:

• A. lens and the object
• B. lens and the screen
• C. object and the screen
• D. lens and the screen and also object and the screen

Answer 1

The correct option is B lens and the screen

When ray comes parallel to the axis of lens then the image will be formed Sharp at the focus.

According to the question,

Image is forming at the screen then student needs to measure the distance between lens and the screen.

Option B