What is the distance of separation between second and third orits of H-atom?

How would the angular separation of interfernece frings in Young's double slit experiment change when the distance of separation between the slits and the screen is doubled?

What is the importance of third 'R's?

What is the distance between two consecutive nodes?

What is the distance between two consecutive antinodes or nodes?

In longitudinal wave,what is the distance between a compression and its nearest rarefaction?

The ratio of the radius difference between 4^(th) and 3^(rd) orbit of H-atom and that of Li^(2+) ion is :

What is the difference between an atom and an ion?

What is the distance between a node and an adjoining antinode in a stationary wave?

A body is released from a great height and falls freely towards the earth. Exactly one sec later another body is released. What is the distance between the two bodies 2 sec after the release of the second body ?