Question

c) A concave mirror has a focal length of 10 cm. An object is placed at 20 cm in front of this mirror.
With the help of ray diagram show where should the screen be placed to get a sharp image of
the same size?
What will be the characteristics of the image formed ?
​

Answer 1

Answer:

Given:

Focal length of concave mirror, f = -20 cm

Distance of object from the mirror, u = -10 cm

use formula, 1/v + 1/u = 1/f

or, 1/v = 1/f - 1/u

or, 1/v = 1/-20 - 1/-10

or, 1/v = -1/20 + 1/10 = 1/20

or, v = +20cm

hence, image position is the 20cm right side from the pole of the concave mirror as shown in the diagram. The image is straight and bigger than the object