Question

A student measures the focal length of a convex lens by putting an object pin at a distance u

Answer 1

i hope this is useful to you

Answer 2

For refraction through a convex lens, lens equation must be satisfied.

Thus  

v

1

​  

−  

u

1

​  

=  

f

1

​  

=constant

where u is always negative by convention  

The equation obtained is of a hyperbola.

Hence the correct graph is represented in option A.