What do you understand by elevation and angular distance between two stars ? How does angular measurement help us to determine. Size of astronomical objects and distances.

What do we understand by polarisation of a wave?How does this phenomenon heolp us to decide,whether a given wave is trnsverse or longitudinl in nature?

What do you understand by the statement 'Light from the sun is unpolarised'? Explain how does sunlight get polarized by the process of scattering.

Hertz,in his historical experiment ,produced stationary electromagnetic waves and measured the distance between two successivendoes.Explain,how this measurement enabled him to show that the electromgnetic waves travelled with the same speed as the speed of lght.

What is the minimum angular separation between two stars ,if a telesope is used to observe them witha n objective of aperture 0.2 m?The wavelength of light used is 5,900 A .

What happens to the force between two objects, if the distance between the objects is doubled and tripled ?

How does the force of gravitation between two objects change when the distance between them is reduced to half ?