Creating a null vector of size 10 in NumPy involves initializing an array of size 10 with values that represent a lack of value or undefined value. There are several ways to create a null vector in NumPy, such as using np.zeros(), np.empty(), np.full() or np.ndarray().

Here we are creating a one-dimensional NumPy array of size 10, where all the elements of the array are initialized to 0. A null vector is also known as a zero vector.

1. Using "np.zeros":

You can create a null vector of size 10 using the `np.zeros()` function, which creates an array of zeros of the specified size.

Example:

2. Using "np.full":

You can also create a null vector of size 10 using the `np.full()` function, which creates an array of the specified size and fills it with the specified value.