Question

If focal length of the concave mirror is determined, by using convex lenses of different focal lengths, do you expect any change in the result? If yes, what type of change? If not, why not?

Answer 1

Answer:

No, it is not always constant for a given lens.

1) Focal length depends on refractive index of the material of the lens relative to its surrounding medium because more the refractive index more will be the deviation of light. If a lens is placed in water instead of water its focal lengh increases.

2) Focal length also depends on the wavelength of the light passing through the lens as red light gets less deviated than violet light.