Question

11. An object is placed 10 cm in front of a convex mirror if focal length 20cm the distance of the image form the mirror is:​

Answer 1

Answer:

• Distance of image from mirror = 6.67 cm

Explanation:

Given:

• Position of object, u = -10 cm
• Focal length of convex mirror, f = 20 cm  [focal length of convex mirrors are positive always]

To find:

• Distance of image from mirror =?

Formula required:

• Mirror formula

      1 / f = 1 / v  +  1 / u

[ Where f is focal length of mirror, v is position of image and u is position of image]

Solution:

Let, position of image be v

Using mirror formula

→ 1 / f = 1 / v  +  1 / u

→ 1 / (20) = 1 / v  +  1 / (-10)

→ 1 / v = 1 / (20) + 1 / (10)

→ 1 / v = ( 1 + 2 ) / 20

→ 1 / v = 3 / 20

→ v = 20 / 3

→ v = 6.67 cm

Therefore,

• Image will be formed at a distance of 6.67 cm from the mirror, behind the mirror.