Final answer:
Reflecting tape is used with a digital photo tachometer to measure the rotational speed of an object, by enhancing the reflectivity for accurate sensor readings.
Step-by-step explanation:
Reflecting tape is typically used on a rotating object when using a digital photo tachometer, not an electronic tachometer (stroboscope), centrifugal-type tachometer, or a chronometric tachometer. The digital photo tachometer works by sending a beam of light towards the target object, which is then reflected back by the tape to the tachometer's sensor. By measuring the time between emitted and reflected light pulses, the tachometer calculates the rotational speed of the object.
When a digital photo tachometer is used, placing a piece of reflective tape on the object is crucial because it enhances the reflectivity of the rotating surface, thus ensuring accurate readings by the sensor.