Check out example codes for "unity c# change color of gameobject". It will help you in understanding the concepts better.

Code Example 1

using UnityEngine; 
using System.Collections; 

public class collisionpill : MonoBehaviour 
{      
  	public Color mycolor;       
  	
  	void OnCollisionEnter(Collision other) 
    {         
        if (other.transform.tag == "Pill") 
        {             
        	gameObject.GetComponent<Renderer>().material.color = mycolor;
        }    
    }
}

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