Two polaroids are kept with their transmission axes inclined at 30^o. Unpolarised light of intensity I falls on the first polaroid. Find out the intensity of light emerging from the second polaroid.

Find the polarizing angles for
(i) glass of refractive index 1.5 and
(ii) water of refractive index 1.33.

A man with a near point of 25 cm reads a book which has small print using a magnifying lens of focal length 5 cm.
(a) What are the closest and the farthest distances at which he should keep the lens from the book?
(b) What are the maximum and the minimum magnification possible?

A small telescope has an objective lens of focal length 125 cm and an eyepiece of focal length 2 cm.
(a) What is the magnification of the telescope?
(b) What is the separation between the objective and the eyepiece?
(c) What is the angular separation between two stars when viewed through this telescope if they subtend 1' for bare eye?

A person has farsightedness with the far distance he could see clearly is 75 cm. Calculate the power of the lens of the spectacles needed to rectify the defect.