Write about the subsidiary quantum number $(l)$.

The subsidiary quantum number $(l)$ is also known as the Azimuthal quantum number or orbital angular momentum quantum number.
It defines the three-dimensional shape of the orbital.
Values of $l$: For a given principal quantum number $n$,$l$ can have $n$ values ranging from $0$ to $n-1$. Each shell consists of one or more subshells. The number of subshells in a principal shell is equal to the value of $n$.
For example:
In the first shell $(n=1)$,there is only one subshell,which corresponds to $l=0$.
In the second shell $(n=2)$,there are two subshells,$l=0, 1$.
In the third shell $(n=3)$,there are three subshells,$l=0, 1, 2$.
In the fourth shell $(n=4)$,there are four subshells,$l=0, 1, 2, 3$.
Subshells corresponding to different values of $l$ are represented by the following symbols:

Value for $l$	$0, 1, 2, 3, 4, 5$
Notation for subshell	$s, p, d, f, g, h$

The following table shows the permissible values of $l$ for a given principal quantum number $n$ and the corresponding subshell notation:

$n$	$l$ (Subshell notation)
$1$	$0$ $(1s)$
$2$	$0, 1$ $(2s, 2p)$
$3$	$0, 1, 2$ $(3s, 3p, 3d)$
$4$	$0, 1, 2, 3$ $(4s, 4p, 4d, 4f)$