Question

Sunil conducts an activity using an object of height 10 cm and a convex mirror of focallength 20 cm. He placed the object at a distance of 20 cm in front of the mirror. What is likely to be height of the image produced?*

1 point

1 cm

5 cm

10 cm

20 cm

​

Answer 1

Given:

Height of the object - 10 cm

Focal length - 20 cm

Object distance - 20 cm

To find:

Height of the image

Solution:

As we have given the mirror so we will use the mirror formula to find the distance of the image

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

where

f = +20 cm

u = -20 cm

• $\frac{1}{20} = \frac{1}{-20} +\frac{1}{v}$
• $\frac{1}{v} = \frac{1}{20} +\frac{1}{20}$
• $\frac{1}{v} = \frac{1}{10}$
• v = 10 cm

Hence the distance of the image is 10 cm

Magnification of the mirror is given by

• $M = \frac{-v}{u} =\frac{Hi}{Ho}$
• $\frac{-10}{-20} =\frac{Hi}{10}$
• $\frac{100}{20} =Hi$
• Hi = 5

So,

The height of the image is 5 cm

Answer 2

Answer:

Explanation:

10