check object destroyed and load new scene

I want to check that object is destroyed or not, if object is destroyed then load new scene. here is my script:

 using UnityEngine;
 using System.Collections;
 public class hey : MonoBehaviour {
 void Start(){
     GetComponent<ParticleSystem> ().emissionRate = 0;
 }
 void Update(){
     if (Input.GetMouseButtonDown (1)) {
         GetComponent<ParticleSystem> ().Emit (20);
     }
 }
 void OnParticleCollision(GameObject obj)
 {
     Destroy (obj, 2.0f);
     //here i want to check and then load new scene.. 

      //I try that thing, but failed..nothing happen
        if (object.Equals (obj, null)) { 
         Application.LoadLevel (7);
     }
     //also this one, but nothing happens
     if(gameObject.tag=="fire123"==null){
         Application.LoadLevel (7);
            }
        // also this one too, but failed :-(
         void OnDestroy(){

Application.LoadLevel (7); } }