is_home() or is_front_page() not working in plugin front.php file ?

Hi,
I am using this slider in many pages for home page slider I need to add some condition. To do that I am trying to use below methods in plugin front.php file:

var_dump(is_home()); – false

var_dump(is_front_page()) – false;

var_dump(!is_admin()) – false;

I am getting false values on home page. What is the reason for this?