Question

State clearly how an unpolarised light gets linearly polarised when passed through a polaroid.
Unpolarised light intensity `I_(0)` is incident ` P_(1)` which is kept near another polaroid `P_(2)` whose pass axis is parallel to that of `P_(1)`. How will the intensities of light, `I_(1) and I_(2)` , transmitted by the polarids `P_(1) and P_(2)` respectively, change on rotating `P_(1)`[ without disturbing `P_(2)` ?

Answer 1

The light having vibrations of electric field vector in all possible directions perpendicular to the direction of wave progation is called ordinary light. The light having vibrations field vectors in only one direaction perpendicular to the direction of progation of light is called plane polarised light.
(ii) The value of the sound intensity inversely squared with increasing distance from sound source, i.e with ` 1/r^(2)`
` I alpha 1/(r^(2)) = I_(2)/I_(1) = r_(1)^(2)/r_(1)^(2) Rightarrow I_(2) =I_(1) (r_(1)/r_(2))^(2)`