Q. An object is placed at a distance of 24 cm in front of a convex lens of focal length 8 cm.

(i) What is the nature of the image formed?

(ii) Calculate the distance of the image from the lens.

(iii) Calculate the magnification of the image.

Asked by akshushashu123 | 6th Mar, 2019, 10:00: AM

Expert Answer:

u = - 24 cm 
f = 8 cm ...(focal length of convex lens) 
1 over f equals space 1 over v minus 1 over u

1 over v space equals space 1 over f plus 1 over u

1 over v equals 1 over 8 plus fraction numerator 1 over denominator negative 24 end fraction equals 1 over 12
v space equals space 12 space c m space

T h u s space i m a g e space i s space f o r m e d space a t space a space d i s tan c e space o f space 12 space c m space b e h i n d space t h e space l e n s.
The image is formed to the right so, the image formed will real and inverted.
Magnification of image is given by,
m = v/u = 12/-24 = - 0.5 
This implies that magnification is -0.5 which means image is diminished. 

Answered by Shiwani Sawant | 6th Mar, 2019, 10:34: AM