BULLET DOES NOT EXPLODE WHEN HIT THE ENEMY

// Instantiates a projectile every 0.1 seconds,
// if the Fire1 button is pressed or held down.
var projectile : Rigidbody;
var fireRate = 0.1;

var Velocity : float = 25;

private var nextFire = 0.0;


function Update () {
	
	//If the player holds down or presses the left mouse button
	if (Input.GetButton ("Fire1") && Time.time > nextFire) {
		Shoot();
	}
	
}

//To make our scripting a little more Object-Oriented-Programming, we will create our custom functions as well
function Shoot() {

	//Add fireRate and current time to nextFire
	nextFire = Time.time + fireRate;
	
	//Instantiate the projectile
	clone = Instantiate (projectile, transform.position, transform.rotation);
		
	//Name the clone "Shot" ::: this name will appear in the Hierarchy View when you Instantiate the object
	clone.name = "Shot";
	
	//Add speed to the target
	clone.rigidbody.velocity = transform.TransformDirection (Vector3.forward * Velocity);
	
}

when i shot the enemy bullet does not explode, ı want to see an effect while exploding. if all my script has any problem, could you tell me all steps one by one

For an explosion you could create a particle system FX and add it to a Prefab. Use the Prefab as the Inspector Variable for a script that includes the explosion on impact.

 //Inspector Variable

var explosion		: Transform;

function OnTriggerEnter(other : Collider)
{
	//Check for enemy
	if(other.gameObject.tag == "enemy")
	{
		
		//Create the explosion on impact
		
		if(explosion)
		{
			Instantiate(explosion, transform.position, transform.rotation);
		}
	
		
		//Destroy bullet
		Destroy (gameObject);
	}
}