Question

Which of the following is FALSE?

• A. Simple microscope is also known as magnifying glass.
• B. A ray of light passing through the optical centre of a lens, after refraction from a convex lens, will emerge parallel to the principal axis.
• C. Magnification produced by a lens is related to the object-distance and the image-distance.
• D. Refractive index of a medium is constant

Answer 1

Answer:

B. A ray of light passing through the optical centre of a lens, after refraction from a convex lens, will emerge parallel to the principal axis.

The refractive index of a medium is not always constant. It varies depending on the wavelength of light and the medium. The refractive index of materials varies with the wavelength (and frequency) of light. This is called dispersion and causes prisms and rainbows to divide white light into its constituent spectral colors.