colliaion detection 2d unity code example

Example 1: unity oncollisionenter2d

void OnCollisionEnter2D(Collision2D col)
    {
		//This method will run when your 2D game object
      	//collides with something

      	Debug.Log("Collided");
    }

Example 2: unity 2d collision

void OnCollisionEnter2D(Collision2D col) {
  Debug.Log("Collided with: " + col.gameObject.name);
}