Question

به باور
6. An object of height of 1.5m is placed before concave mirror of focal length 20 cm
so that a real image is formed
at a distance of 60 cm from it & find the position of object
what will be
height of image formed​

Answer 1

Explanation:

Here, m=

u

v

=−4

⇒u=

4

−v

------------(1)

Also, ∣u∣+∣v∣=1.5

4

v

+v=1.5

⇒

4

(v+4v)

=1.5

⇒v=1.2m

So, putting the value of v in equation (1):

u=

4

−1.2

=−0.3m

∴f=

u−v

uv

⇒f=

(−0.3−1.2)

(−0.3×1.2)

=0.24m

Answer 2

Answer:

u is -30cm

height of image is 3cm

Explanation:

Height of object,h1 is 1.5cm

Focal length is -20cm

Image distance is -60cm

Mirror formula,

1/u+1/v is equal to 1/f

1/u is equal to 1/f-1/v

1/u is equal to 1/-20-(1/-60)

1/u is equal to 1/-20+1/60

1/u is equal to -3+1/60

1/u is equal to -2/60

u is equal to -30

m is equal to -v/u

m is equal to -(-60)/-30

m is equal to -2

Height of image is h2

m is equal to h2/h1

h2/1.5 is equal to -2

h2 is equal to -3.0