Question

we are given a convex lens of focal length 20cm draw ray diagram to show the nature size and position of the image formed when the object is kept at a distance of 55 CM

Answer 1

It id hard to draw 55cm
If the focal length is 20 cm then 2F is at (2×20) 40 cm.
This means the object is beyond 2F
Therefore nature and position of image-
1.Real
2.Inverted
3.Diminished
4.Formed between F and 2F

Answer 2

Given:

Focal length (F) of convex lens= 20cm

Distance of object= 55cm

To Find:

Nature, size and position of the image formed.

Solution:

The above ray diagram shows the object AB kept at a distance of 55cm from a convex lens.

Focal length of the lens is given as 20cm.

We know that 2F is twice the length of F.

Then, 2F= 2 × 20= 40cm

Since object is at 55cm, it lies beyond 2F.

Hence, when two light rays- one parallel to principle axis and the other passing through 'O', after refraction through the lens converge and meet at a point between F and 2F of the lens on the opposite side.

The nature of the resultant image (A'B') is- real and inverted.

Its size is smaller than the object.

The image lies between F and 2F.