Question

An object 2cms high is held near a concave mirror of magnification 20. How tall will be the image.
OPTIONS:
(a) 20
(b) 40
(c) - 40
(d) - 20

Answer 1

Correct option is

D

All the above are true

Size of object h

o

=2cm

Size of the object h

i

=?

Focal length f=−12cm

Object distance u=−20cm

Image distance v=?

Using mirror formula

f

1

=

v

1

+

u

1

−12

1

=

v

1

+

−20

1

v

1

=

60

−5+3

v=−30cm

Magnification (M)=

h

o

h

i

=

u

−v

=

−20

30

=−1.5

h

i

=−1.5×2= −3cm

Image will be real, inverted and magnified.

Answer 2

$\huge\bf\underline\red{❦︎Answer❦︎}$

(b) 40

Given that the height of the object, h1= 2cm

Let h2 be the height of the image.

Given that the magnitude, m=20

Solution:-

i.e= m= h2/h1

20= h2/2

☞︎︎︎h2= 20×2= 40cm

Therefore the height of the image= 40cm

The image will be 40cm tall

Explanation:

ʜᴏᴘᴇ ɪᴛ ʜᴇʟᴘs ʏᴏᴜ

ᴘʟᴇᴀsᴇ ғᴏʟʟᴏᴡ ᴍᴇ