What are the applications of pumping lemma?

Pumping lemma is used to check if a language is regular or not.
(i) Assume that the language (L) is regular.
(ii) Select a constant ‘n’.
(iii) Select a string(z) in L, such that |z|>n.
(iv) Split the word z into u,v and w such that |uv|<=n and |v|>=1.
(v) You achieve a contradiction to pumping lemma that there exists