Question

An obiect at 10 cm high is placed at distance of so can brow a focal length 25 cm. Find the size of the image .​

Answer 1

Answer:

Solution

H1 = +2.5cm

u = -25cm

f = +20cm

1/f = 1/v + 1/u

1/20 = 1/v -1/25

1/v = 1/20 + 1/25

1/v = 9/100

v = +11.11 cm

m = h2/h1 = -v/u

h2/2.5 = -11.11/-25

h2 = +1.11 cm

Hence the image will be formed at 11.11 cm behind the mirror, which will be virtual, erect and of 1.11cm

Answer 2

Explanation:

H1 = +2.5cm

u = -25cm

f = +20cm

1/f = 1/v + 1/u

1/20 = 1/v -1/25

1/v = 1/20 + 1/25

1/v = 9/100

v = +11.11 cm

m = h2/h1 = -v/u

h2/2.5 = -11.11/-25

h2 = +1.11 cm

Hence the image will be formed at 11.11 cm behind the mirror, which will be virtual, erect and of 1.11cm size.