Question

37. An object 10 cm high is placed at the principal focus
of a concave lens of focal length 20 cm. Find the
position, size and nature of the image.​

Answer 1

Answer:

height of object= 10cm

f=20cm

position will be at infinity

size will be highly enlarged

nature will be real and virtual

Explanation:

this is because when we put an object at focus image is formed at focus.

Here measurements are given just to confuse, this is not required.

Answer 2

Answer:

When the object is taken between p & f ,

then the image forms behind the mirror.

The nature of the image is enlarged & erect & also the image is known as virtual image

Explanation: