Question

An object is placed at a distance of 40cm before a concave mirror of focal length 30cm. find the distance of the image formed​

Answer 1

Answer:

120cm on the same side of the object

Explanation:

Here, f = -30 cm, u = -40 cm

Image distance can be calculated as follows :

1/f = 1/u + 1/v (mirror formula)

1/-30 = 1/-40 + 1/v

1/v = 1/40 - 1/30

1/v= 3-4 / 120

1/v= -1/ 120

v= -120 cm .

here the negative sign indicates that the image is formed on the same side of the object.

Answer 2

Answer:

-120 cm

Explanation:

u=-40cm

f=-30cm

v=?

we know that,

Mirror formula=1/f=1/v+1/u

1/-30=1/v-1/40

1/-30+1/40=1/v

-4+3/120=1/v

-1/120=1/v

v=-120cm