Question

An object of size 1cm is placed at a distance of 15cm in front of a convex lens of focal length 10cm . Find the nature, size, location of the image

Answer 1

Given,

Focal length f = + 10 cm (convex lens)

Image distance u = - 15 cm

We know,

From Len's formula,

$\frac{1}{v}-\frac{1}{u}=\frac{1}{f}$

Putting all the values

$\frac{1}{v}+\frac{1}{15}=\frac{1}{10}$

After solving

v = 30 cm

So image will be formed at 30 cm behind the lens

Now given

Size of object= 1 cm

Using the formula of magnification for lens

$m=\frac{-v}{u}$

Putting all the values

$m=\frac{-30}{-15}=2$

Hence the magnification is 2

Size of the image will be greater than the size of the object and the image will be virtual.