Question

Focal length of a convex lens recorded by three students is10.1 cm, 10.2 cm and 10.0 cm. Find the mean focal length of the convex lens​

Answer 1

According to lens maker formula,

f

1

​

=(μ  

g

​

−1)  

R  

1

​

 

1

​

−  

R  

2

​

 

1

​

 

10

1

​

=0.5  

R  

1

​

 

1

​

−  

R  

2

​

 

1

​

 

5

1

​

=  

R  

1

​

 

1

​

−  

R  

2

​

 

1

​

 

5

1

​

=  

75

1

​

−  

R  

2

​

 

1

​

 

R  

2

​

 

1

​

=−  

5

1

​

+  

75

1

​

 

R  

2

​

 

1

​

=  

15

−3+2

​

 

R  

2

​

=15cm