Question

An objects is placed at 30 cm in front of a concave mirror of focal length 20 cm, where is the image formed ?An objects is placed at 30 cm in front of a concave mirror of focal length 20 cm, where is the image formed ?​

Answer 1

Given :

u=-30cm

f=-20cm

Concave mirror

We are asked:

Image of object=v

Solution :

According to mirror formula

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

$\frac{1}{ - 20} = \frac{1}{v} + \frac{1}{ - 30}$

$\frac{ - 1}{20} + \frac{1}{30} = \frac{1}{v}$

$\frac{ - 1}{60} = \frac{1}{v}$

Thus, v=-60cm

We can verify that as (-) sign is there Image is formed Real and inverted