MODEL QUESTIONS (IPE PATTERN)

Derive an expression for a thin double convex lens. Can you apply the same to a double concave lens too?

Obtain an expression for the combined focal length for two thin convex lenses kept in contact and hence obtain an expression for the combined power of the combination of the lenses.

Define Snell's Law. Using a neat labelled diagram derive an expression for the refractive index of the material of an equilateral prism.

A ray of light, after passing through a medium, meets the surface separating the medium from air at an angle of $45°$ and is just not refracted. What is the refractive index of the medium?

Draw a neat labelled diagram of a compound microscope and explain its working. Derive an expression for its magnification.

A person looking at a person wearing a shirt with a pattern comprising vertical and horizontal lines is able to see the vertical lines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision corrected?

A man with normal near point ($25 \mathrm{cm}$) reads a book with small print using a magnifying glass: a thin convex lens of focal length $5 \mathrm{cm}$. What is the closest and the farthest distance at which he should keep the lens from the page so that he can read the book when viewing through the magnifying glass?

A man with normal near point ($25 \mathrm{cm}$) reads a book with small print using a magnifying glass: a thin convex lens of focal length $5 \mathrm{cm}$. What is the maximum and the minimum angular magnification (magnifying power) possible using the above simple microscope?