10. A student has a bright idea for a generator that apparently generates electric energy without a corresponding loss of energy somewhere else. His suggested arrangement is shown in ▼ Figure 20.22.

The magnet is initially pulled down and released.

When the magnet is attached to a spring, the student thinks that there should be a continuous electrical output as the magnet oscillates. What is wrong with this idea? [Hint: Check the total energy stored in the spring – magnet system and the forces on the magnet as it oscillates.]