Out of order Please help

Hello everyone,
My problem is i have a ball(sphere).
i have added this script to it

function FixedUpdate () 
{
        if(Input.GetMouseButton(0))
		rigidbody.AddRelativeForce (12, 200, 0);	
}

and i have this added to my sphere but no matter where i click it still works.
i want it to work only when i click on the sphere.
what this script does actually makes the sphere bounce when i click it.
Please help!.

GetMouseButton triggers whenever you click mouse button doesn’t matter where the cursor is not only at the object with attached script.
So you should check whether mouse cursor is over your object. You can do that by raycasting.
Set Tag of the object to for example “TouchBall” and use:

function FixedUpdate()
{
  Ray ray;
  RaycastHit hit;
  if (Input.GetMouseButton(0))
    {
        ray = Camera.main.ScreenPointToRay (Input.mousePosition);
        if (Physics.Raycast (ray, out hit))
        {
            if (hit.collider.tag == "TouchBall")
            {
                rigidbody.AddRelativeForce (12, 200, 0); 
            }
        }
    }
}