How do detect when an Object is touched

I have a bomb and want it to explode when touched. I just tried implementing this with ray-casting but something isn't working. I'm using unity 2d settings.

Also I'm programming this on a computer(of course) so is there some setting I have to set to make it recognize mouse clicks as touches?

 #pragma strict
 var explosion:GameObject;
 
 
 function Update () {
     for (var i = 0; i < Input.touchCount; i++) {
         if (Input.GetTouch(i).phase == TouchPhase.Began) {
         
             // Construct a ray from the current touch coordinates
             var pos:Vector3 = Camera.main.ScreenToWorldPoint (Input.mousePosition);
             var hitInfo:RaycastHit2D = Physics2D.Raycast(pos, Vector2.zero);
             if (hitInfo != null && hitInfo.collider != null) {
                 Debug.Log ("I'm hitting "+hitInfo.collider.name);
                 var whatsHit:GameObject = hitInfo.collider.gameObject;
                 
                 if(whatsHit.CompareTag("bomb")){
                     whatsHit.GetComponent(BombScript).Explode(whatsHit.transform.position);
                 }
             } else {
                 Debug.Log("hitting nothing");
             }
         }
     }
 }
 
 function Explode(pos:Vector3){
     GameObject.FindGameObjectWithTag("GameController").GetComponent(BombSpawner).spawnBomb = true;
     Instantiate(explosion, pos, Quaternion.identity);
     Destroy (this.gameObject);
 }