Question

How does the focal length of a convex lens change if monochromatic red light is used instead of violet light​

Answer 1

Answer:

focal length of red light increases

Explanation:

The refractive index of a medium is inversely proportional to the wavelength of light used.

Thus, μR<μV

Now, f1=(μ−1)(R11−R21)

Thus, fR>fV

Answer 2

Answer:

Focal length of the convex lens increases with the increase in wavelength. We know wavelength of red is more than the wavelength of violet. So, as the wavelength decreases the focal length also decreases.