The schematic diagram below shows a wave-energy generator prototype. It consists of a strong cylindrical permanent magnet suspended from a spring inside a fixed vertical copper coil. The two ends of the coil are connected to a sensitive centre-zero microammeter.
An ocean wave causes the magnet to oscillate vertically.
Explain the observations seen on the microammeter as the magnet is pulled upwards through the centre of the coil, becomes momentarily stationary at its highest point, and then falls back downwards.