Question

Why is it beneficial to perform focal point of a convex lens exercises in a dimly-lit room?

What is the focal length of a convex lens that produces an image on a screen 40 cm away with an object placed 10 cm from the lens? What is the magnification? Is the image inverted or upright? Show all calculations in your answer.

Answer 1

Step-by-step explanation:

It is given that,

The object distance from the lens is 10 cm, u = -10 cm

Image is formed at a distance of 40 cm away from the lens, u = 40 cm

The lens formula is :
`(1)/(v)-(1)/(u)=(1)/(f)`, v is image distance

`(1)/(40)-(1)/(-10)=(1)/(f)\\\\f=8\ cm`

The focal length is 8 cm

Magnification,

`m=(v)/(u)\\\\m=(40)/(-10)\\\\m=-4`

The magnification is negative, it means that the formed image is inverted.