Question

18. An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal
length 18 cm. At what distance from the mirror should a screen be placed, so that
a sharp focussed image can be obtained? Find the size and the nature of the image.
this?​

Answer 1

Answer:

I = -14cm and the nature of image is real, inverted and magnified image

Explanation:

Given:

size of object(O)=7cm

distance of object(u)= -27cm

focal lenght of concave mirror(f) = -18 cm

Let us take size of image be 'I'

so we know the mirror formal here we applied that formula

1/v + 1/u = 1/f

so putting value of u and v

1/v = 1/-18 - 1/-27

1/v = 1/-54

so v = -54 cm

So image is formed on object side only.

Magnification,

m = -v/u = I/O

here I= image and O= object

now put value of v and u in the formula of magnification

m= -54/-27 = I/7

so

I= -14cm

so image is double in size to the object

the size of image is -14cm

And

Nature:- Real, inverted and magnified image