Question

A student focused the image of the candle flame on a white screen using a convex lens .he noted down the position of candle screen and lens as under position of candle =12cm ,position of convex lens = 50 cm ,position of screen = 88 cm ,what is focal length of the convex lens ,where will the image be formed if she shifts the candle towards the lens at a position of 31 cm what will be the nature of the candle if he further shifts the candle toward lens draw a ray diagram to show the formation of image in case 3

Answer 1

Answer:

( i ) .  Object distance u = 50 - 26 = 24 cm

Image distance v = 74 - 50 = 24 cm .

Since object distance is equal to image distance.

2 f = 24

= > f = 12 cm

So , focal length of object is 12 cm.

( ii ) . u = 50 - 38 = 12 cm

It's mean candle is at focus.

= > Image will form at infinity.

( ii ) Refer to attachment for ray diagram.