int photoresistor = A2, light = A0, inp = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(photoresistor, INPUT);
  pinMode(light, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  inp = analogRead(photoresistor);
  float voltage = inp / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(50 * 1e3 * pow(10, 0.7) / resistance, (1 / 0.7));
  Serial.println(inp);
  if(lux < 500)
    digitalWrite(light, HIGH);
  else
    digitalWrite(light, LOW);
  delay(1000); // this speeds up the simulation
}