Physics2D.Raycasting questions

Having a problem understanding, and setting up raycast for a 2D project. Right now im currently trying to set it up to where I draw the ray with debug.drawline and want it to give me a message of hitting target when the ray hits a other collider. After that I wanna implement a rough shooting mechanic.

my current code

using UnityEngine; using System.Collections; public class Control : MonoBehaviour { // Update is called once per frame void Update () { Physics2D.Raycast (transform.position, Vector2.up, 25f); Debug.DrawLine (transform.position, Vector2.up, Color.red); } } couple of questions are is transform.position ok for the orgin. Do vector 2 work for it or do I have to use vector3, Im not using layermasking so do I have to add that into my parameters. what wil be the more effiect way to draw the line?

sorry If im asking such noob questions but I wanna understand this completely because I see how important it is understanding code in video game development.