An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.

Answer:
Object distance, u = -25 cm
Object height, ho = 5 cm
Focal length, f = +10 cm
According to the lens formula,



The positive value of v shows that the image is formed at the other side of the lens.

Magnification of lens, m=\(\frac{image distance }{object distance} \) = \(\frac{v}{u} \)

m=\(\frac{v}{u} =\frac{16.66}{-25} =-0.66 \)
The negative sign shows that the image is real and formed behind the lens.

m = \(\frac{Image height}{object height} = \frac{hi}{5} \) ;

hi = m x ho = -0.66 x 5 = -3.3 cm

The negative value of image height indicates that the image formed is inverted.

The position, size, and nature of image are shown in the following ray diagram.