Define the term 'linearly polarised light' . When does the intensity of transmitted light become maximum when a polaroid sheet is roatated between two crossed polaroids?

Two slits are 1mm apart and a screen is placed at some distance. When the slits are illuminated with light of wavelength 500nm, fringe separation obtained on the screen is 0.5mm. What is the distance between the screen and the slits?

Explain polarisation. Show with a diagram how a light beam through two polaroids.

In a Young's double slit experiment distance between the slits is 1 mm. The fringe width is found to be 0.6 mm. When the screen is moved through a distance of 0.25 m away from the plane of the slit, the fringe width becomes 0.75 mm. Find the wavelength of light used.

The nearest star to our solar system is 4.29 light years away. How much is this distance in terms of parsecs? How much parallax would this star (named Alpha Centauri) show ,when viewed from two locations of the Earth six months apart* in its orbit around the Sun?