Why is the metal ball not moving when I use another frequency but it moves when I use the test frequency?Updated a year ago

The reason why the metal ball is responsive during the test frequency but not some other frequencies is due to the Hz rating of the given frequency. The test frequency is a vortex field of 20Hz, this means that the oscillation is occurring 20 times per second and the ball moves. When we go to a higher frequency such as anything over 50Hz or so, the frequency becomes too fast for the ball to respond. This doesn't mean that the device is not working, it just means that the frequency is too high and too fast for there to be enough time to create a back and forth movement in the ball or magnet. And because the ball/magnet can't keep up with the fast oscillations, it appears to be still. This is natural and doesn't indicate any barrier to the performance of the frequencies.