Question

The image of an object formed by a mirror is real and inverted and is of magnification 1. If the image is at a distance of 30 cm from the mirror where is the object placed . Find the position of the image if the object is now moved 20 cm towards the mirror. What is the nature of the image obtained ? Justify your answer with the help of Ray diagram. "Please help me."

Answer 1

Given the image formed is real inverted and its magnification is -1

if magnificaion is -1 then it means the nature of the image is real invertedand of the same size . in this case the object is placed at C and image is formed at C.

if the image is at a distance of 30cm from the mirror then the object is also at a distance of 30cm from the mirror.

if the object is moved 20cm towards the mirror then the position of the object is between the pole and the principal focus  (f=15cm)

When the object is moved 20cm towards the mirror then the nature of the image is virtual erect and enlarged

look the attachment for the diagram

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.