Question

An object of height 2.5 cm is placed at a distance of 15 cm from the optical centre '0' of a convex lens of focal length 10 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical centre '0', principal focus F and height of the image on the diagram.(All India - 2016)

Answer 1

Answer:4cm

Explanation:

Answer 2

Let us solve for it

Explanation:

Height of object = 2.5cm

Distance of object (u)=15cm = -15cm

Focal length of convex lens (f)=10cm = -10cm

Image distance (v)=?

Size of image =?

Applying lens formula :

$1/v-1/u=1/f\\1/v-1/(-15)=1/(-10)\\1/v= -1/10-1/15\\v= -6cm$

$let us find the magnification now :\\m=v/u\\m=-6/-15\\m=2/5\\Height of image\\=?m= hi/ho\\2/5=hi/2.5\\height of image = 1cm$