What is an orbital? How is it different from Bohr's orbit ?

Radius of 3rd Bohr orbit is

The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?

Radius of 3^(rd) Bohr orbit is

How many elliptical orbits are added by Sommerfeld in third Bohr's orbit? What was the purpose of adding these elliptical orbits ?

What is the difference between an orbit and orbital ?

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter - orbit jumps of the electron for Bohr orbits in an atom of hydrogen ?