Question

A concave lens of focal length 12 cm forms an image 8 cm from the lens. How far is the object placed from the lens? please answer it correctly​

Answer 1

Answer:

Given: f=−15

v=−10

From mirror formula,

v

1

−

u

1

=

f

1

−10

1

−

u

1

=

−15

1

u

1

=

15

1

−

10

1

u=−30 cm

Answer 2

Answer:

30 cm

Explanation:

Given: f=−15

           v=−10

From mirror formula,  

v

1

​

−  

u

1

​

=  

f

1

​

 

                                     

−10

1

​

−  

u

1

​

=  

−15

1

​

 

                                     

u

1

​

=  

15

1

​

−  

10

1

​

 

                                   u=−30 cm