Request a call back

An object is placed at a distance of 25cm from a mirror. The mirror produces an image that is 20 cm (i) behind the mirror; and (ii) in front of the mirror. For each case, find focal length of the mirror and nature of mirror.
Asked by sharmaayush7777777 | 19 Jun, 2019, 10:17: AM
The object is placed at the distance of 25 cm from the mirror.
u = -25 cm

The image is produced at 20 cm
i) In first case,
the image is in front of mirror.
Thus the image is on the same side as that of an object.
Thus v = -20 cm
By using mirror formula

Thus, when the image is formed in front of the mirror, the focal length of the mirror is 11 cm.
As the focal length is negative, the mirror is concave mirror.

ii) In second case the image is formed behind the mirror at 20 cm from the mirror.
Thus, the image is to the right side of the mirror.

Thus, by using the mirror formula,

Thus, when the image is formed behind the mirror, the mirror is convex mirror because the focal length of the convex mirror is positive and the image is always formed behind the convex mirror.
Answered by Shiwani Sawant | 19 Jun, 2019, 02:15: PM

Application Videos

CBSE 10 - Physics
Asked by ruchipandey20071978 | 11 May, 2023, 06:53: AM
CBSE 10 - Physics
Asked by priyanshdhiman2008 | 17 Mar, 2023, 09:17: AM
CBSE 10 - Physics
Asked by piustoppo9thb | 24 Jun, 2022, 09:58: PM
CBSE 10 - Physics
Asked by priyankakiran2017 | 22 Jun, 2022, 07:07: PM
CBSE 10 - Physics
Asked by topperlearningforcontent | 02 Feb, 2022, 03:32: PM
CBSE 10 - Physics
Asked by bibektripathy17 | 15 Jun, 2021, 09:13: AM