Question

If an object is placed at a distance of 60cm from a concave mirror and the virtual image of the object is formed at 20cm from the mirror . The focal length of the mirror will be​

Answer 1

Answer:

Given, Magnification, m=−  

u

v

​  

 

2

1

​  

=−  

60

v

​  

 

v=−30cm

From lens formula,  

f

1

​  

=  

v

1

​  

−  

u

1

​  

 

f

1

​  

=  

−30

1

​  

+  

−60

1

​  

 

f

1

​  

=−  

60

−2−1

​  

=  

60

−3

​  

 

f=−20cm

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Step-by-step explanation:

Answer 2

Step-by-step explanation:

20m of scale can be used in maths