Touch Less Door bell

int trigPin = 9;
int echoPin = 8;
int Buzzer = 11;
void setup() {
Serial.begin(9600); 
pinMode(Buzzer, OUTPUT);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
void loop() {
long duration, distance;
digitalWrite(trigPin,HIGH);
delayMicroseconds(1000);
digitalWrite(trigPin, LOW);
duration=pulseIn(echoPin, HIGH);
distance =(duration/2)/29.1;
Serial.print(distance);
Serial.println("CM");
delay(10);
if((distance<=10)) 
{
digitalWrite(Buzzer, HIGH);
}
else if(distance>10)
{
digitalWrite(Buzzer, LOW);
}
}