Basic Understanding of Digital Output Pins using Ohm's law

Other Hardware General Electronics
4

My code is really simply, it's just

void setup()
{
  pinMode(3, OUTPUT);
}

void loop()
{
  digitalWrite(3, HIGH);
  delay(1000); // Wait for 1000 millisecond(s)
  digitalWrite(3, LOW);
  delay(1000); // Wait for 1000 millisecond(s)
}

Untitled drawing
Untitled drawing960×720 46.4 KB

I'm not sure if the photo is going to show up, but I'm simply attaching the multimeter to each side of the resistor.