Question

Find the size, nature and position of image formed when an object of size 1 cm is placed at a distance of 15 cm from a concave mirror of focal length 10 cm.

Answer 1

Answer

u=−15cm

f=−10cm

h=1cm

From mirror formula

f

1

​

=  

u

1

​

+  

v

1

​

 

v

1

​

=  

f

1

​

−  

u

1

​

 

v

1

​

=  

−10

1

​

−  

−15

1

​

 

v=−30cm

The image is formed at a distance 30cm on the left side of the mirror from the pole.

m=  

h

h  

′

 

​

=  

u

−v

​

 

h  

′

=−1×  

−15

−30

​

 

h=−2cm

The image size is 2cm and it is real and inverted.