Question

m air the position and nature of the alor 4. An object placed 20 cm in front of a mirror is found to have an image 15 cm (a) in it. (b) behind the mirror. Find the focal length of the mirror and the kind of mirror f2 cm from a diyerning racted we case​

Answer 1

Answer:

Object diatance: u=20 cm

Image distance: v=15 cm

CASE-1: The object and the image are on the same side:

Mirror formula: 1/F​=1/V+1/U​

∴1/F​=−151​−201​  (As both u and v are negative)

⇒f=−760​cm

As the focus is negative, so the mirror will be a concave mirror.

CASE-2: The object and the image are on the opposite sides:

Using the mirror formula: 1/F​=1/V+1/U​

f1​=151​−201​    (here u is negative but v is positive)

⇒f=60cm

As the focus is positive, so the mirror will be a convex mirror.

Answer 2

Answer:

Explanation:

U can use formkla 1/f=1/v+1/u