Does change in URL File Extension affect SEO ?

I am trying to change my URL from
www.domain.com/abc.php to www.domain.com/abc/

did you notice that abc/ no file extension there

so, if i apply this pattern to my site will this effect me in SEO?

 

Yes, it will affect. If you use wordpress there are some plugin which will redirect (301) your old links to the new ones without affecting on-site SEO.

 

actually i don't want to show my file extension in url... even then also this will effect my SEO?

 

I think it will effect as google considered both page individual like domain name with www. or without www.

 

ya its give effect
It led to problems with search engines like Google indexing both