Question

How many p-orbitals participate in the hybridization of nitrogen in pyrrole?

Answer 1

In pyrrole, the nitrogen atom has a lone pair and 3 sigma bonds.
But the lone pair is delocalised inside the ring and responsible for aromatic character of pyrrole.
The unavailibility of the lone pair and partial double bond character with $N-C$ bonds cause the nitrogen to attain an $s{p}^2$-hybridisation.