Use of IR sensor with Arduino uno, Object detection with LED glowing continue after removing object

Led control with IR sensor using arduino.
Arduino Uno.
LED continuous glowing after removing object in front of the IR sensor.

Arduino Uno with IR sensor.

Components required for this project.
1 Arduino Uno
1 IR sensor
1 LED
Few Jumper wires
1 USB cables

[diba]

Hey what about the spectrum to detect the objects ? it is like a laser which is linear or it can detect objects on a range depending on the distance ?

I want to detect water leaks and see if this sensor can detect falling water streams.