Question

An object of height 8 cm is placed at a distance of 25 cm in front of a lens having radius of curvature 30 cm . The image of an object

is obtained on the screen. Determine the nature of lens used. Also find the nature,

size and position of image formed​

Answer 1

ANSWER

Mirror formula :

 

v

1

​  

+  

u

1

​  

=  

f

1

​  

...........(1)

So, u=−25cm

Concave mirror have negative focal length.

f=−8cm

Putting the values in (1),

v

1

​  

+  

−25

1

​  

=  

−8

1

​  

 

We get , v=−54cm

Also,

Magnification =  

h  

1

​  

 

h  

2

​  

 

​  

=  

u

−v

​  

 

7.0

h  

2

​  

 

​  

=−  

−27

−54

​  

 

h  

2

​  

=−14.0cm

Image will be real and inverted and will be of size 14 cm.