Final answer:
To make a motion detector respond to faster movements, you reduce the distance between the detectors or decrease the time delay, allowing for quicker detection of motions. The correct option is b. Reduce the distance between the detectors and/or decrease the time delay.
Step-by-step explanation:
If you want a motion detector circuit to respond to faster object motions, changes can be made to either the distance between the detectors or the time delay. To make a motion detector respond faster, you need to adjust these parameters to allow the detector to pick up on quick movements more readily. If you reduce the distance between the detectors, it means that the object doesn't have to travel as far to trigger the next sensor, allowing for quicker detection. Conversely, decreasing the time delay means the circuit will react more swiftly to the detected motion.
Considering the options provided, the correct option is b. Reduce the distance between the detectors and/or decrease the time delay.
For example, if you reduce the distance that the object travels by half while keeping the time constant, the motion detector will respond to faster movements as the object will quickly trigger the sensors in succession. Similarly, if you keep the distance constant and reduce the time delay by half, this also enables the circuit to respond more quickly to motion, as it requires less time to pass before it can detect a subsequent movement.
Therefore, both adjustments serve to increase the sensitivity of the motion detector to quick movements, making it more responsive.