NCIDQ IDFX Practice Exam

How does reflectorless electronic distance measurement determine distance?

1. By measuring the time taken for a signal to return

2. By relying on a laser beam returned from a reflective prism

3. By bouncing a signal from the object being measured

4. By using a mechanical measuring tape

The correct answer is: By bouncing a signal from the object being measured

Reflectorless electronic distance measurement (EDM) determines distance by sending a signal, typically a laser or infrared beam, towards an object and then measuring the time it takes for that signal to bounce back to the device. This method allows for direct distance measurement to the object without the need for a reflective prism or any other target. By calculating the time taken for the signal to return and knowing the speed of light, the device can accurately determine the distance between the EDM instrument and the object. The use of a direct bounce off the object being measured is crucial because it allows for greater flexibility in measuring distances to a wide range of surfaces without requiring additional equipment or setup. This is particularly advantageous in situations where placing a reflective target is not feasible. Other approaches, such as the reliance on a reflective prism which would be needed in other methods, are not applicable here. Unlike a mechanical measuring tape that provides a direct but manual measurement, electronic distance measurement benefits from the speed and precision of electronic methods, allowing quick and accurate readings over various ranges and conditions.