can use abstract class so why u used interface in your appli

Question

hi frnds

Please give the ans with your experience it will be good for me so which I can be explain the interviwer..

1..i know abstract class and interface but I want to know that

Give the example for both and where u used in your project

And we can use abstract class compare to interface???

Interviwered asked me u can use abstract class so why u used interface in your application…

Please share the ans with your concept///I searched in internet but I confused???