Question

An object 4 cm in size is placed at a distance of 25 cm from a concave mirror of focal length 15 cm. Find the position, nature and height of the image.​

Answer 1

Explanation:

Focal length, f=15cm

Object distance, u=25cm

Object height, h

0

=4cm

From mirror formula,

f

1

=

v

1

+

u

1

−15

1

=

−25

1

+

v

1

⇒

v

1

=

−15

1

+

25

1

v=−37.5cm

magnification, m=−

u

v

=

h

0

h

i

⇒m=−

−25

(−37.5)

=

4

h

i

h

i

=−

25

37.5×4

h

i

=−6cm

To get a sharp image, v=37.5cm

The image is real, inverted and magnified

Answer 2

Answer:

Explanation:

Given :

Object distance u = 25 cm

Focal length f = 15 cm

We have mirror formula :

1 / f = 1 / v + 1 / u