what are delta orbitals?

Q. How many nodal planes are present in $\delta$ bonding molecular orbital?

Q. What are Orbitals??

Q. What are degenerate orbitals?

Q. The orbitals that can form $\delta$ bond among the following is:

Q. When an object is in a circular orbit of radius $r$, its time period of revolution about the earth is $T$ and orbital velocity is $v$ when its orbit is $r+$$\Delta$r. Find the change in time period $\Delta$T and orbital velocity $\Delta$v.