Given :
An object 50 cm high is placed 1 m in front of a converging lens whose focal length is 1.5 m.
To Find :
the image height (in cm).
Solution :
By lens formula :
[tex]\dfrac{1}{v} - \dfrac{1}{u} = \dfrac{1}{f}[/tex]
Here, u = - 100 cm
f = 150 cm
[tex]\dfrac{1}{v} - \dfrac{1}{-100} = \dfrac{1}{150}\\\\v = - 300 \ cm[/tex]
Now, magnification is given by :
[tex]m = \dfrac{v}{u} = \dfrac{h_i}{h_o}\\\\h_i = \dfrac{300}{100}\times 1\\\\h_i = 3 \ m[/tex]
Therefore, the image height is 3 m or 300 cm.
