After going through out the unity forum and some blogs and website..here is my solutions which I find the for the universal resolution for all mobiles and tablets in unity...while developing 2d games in unity just we have to play with orthographic size...here is the code..
void start( )
{
Var height=camera. main.orthographicsize*2;
var width=height*screen.width/screen.height;
transform.local scale=new vector3(width,height, 1.0f);
}
void start( )
{
Var height=camera. main.orthographicsize*2;
var width=height*screen.width/screen.height;
transform.local scale=new vector3(width,height, 1.0f);
}