Thera are many differences between abstract class and interface in php.

1. Abstract methods can declare with public, private and protected. But in case of Interface methods declared with public.

2. Abstract classes can have constants, members, method stubs and defined methods, but interfaces can only have constants and methods stubs.

3. Abstract classes doest not support multiple inheritance but interface support this.

4. Abstract classes can contain constructors but interface doest not support constructors.

BY Best Interview Question ON 13 Jan 2019