Question

the image of an object formed by a mirror is real inverted and of magnification -1 if the image is a at a distance of 30cm from the mirror where is the object placed find the position of the image if it has moved 20cm towards the mirror what is nature of image justify ur answr with the help of a ray diagram

Answer 1

when the image is formed real inverted and with magnification -1 then object is kept at c  [centre of curvature].

if the image is at distance of 30 cm then the object is placed at c.

if the object is moved 20cm towards the mirror then 30-20= 10.

then U=10cm, then the nature of image is real inverted enlarged.

then the object is kept between fand c image formed beyond c

Answer 2

Answer:

+ 30 cm

Explanation:

Given :

Magnification = - 1

Image distance = 30 cm

We know

m = - v / u

- 1 = 30 / u

u = - 30 cm

Now we have ,

1 / f = 1 / v + 1 / u

1 /  f = 1 / - 30 - 1 / 30

f = - 15 cm

When object moved 20 cm

u' = - 30 + 20 = - 10 cm

We have f = - 15 cm

We have to find new image distance v'

Again ,

1 / f = 1 / v' + 1 / u'

- 1 / 15 = 1 / v' - 1 / 10

1 / v' = 1 / 30

v' = 30.

Nature of image as :

Virtual

Erect

Magnified.