Click on GameObject leads to multiple call

Questions & Answers
1

Hey guys facing a strange issue.While detecting the click on gameobjects using Raycasting,sometimes the code gets executed multiple times. Here is the code

void Update () 
{
	if (Input.GetMouseButton(0)) 
   	{
		Ray ray;
		RaycastHit raycast;
		ray=Camera.mainCamera.ScreenPointToRay(Input.mousePosition);
		if(Physics.Raycast(ray,out raycast))
		{
			switch( raycast.collider.name)
			{
				case "First_Sphere":
					GameObject go = (GameObject)Instantiate(Resources.Load("1ValenceBondElementPrefab"),new Vector3(0,0,0),Quaternion.identity); 
				break;
					
			}		
		}
	}	
}

What leads to this multiple calling and why sometimes it leads to multiple calls and sometimes it is executed properly

2

Look up Unity - Scripting API: Input

GetMouseButton checks if it is clicked or held. GetMouseButtonDown checks it was first pressed this frame.