Final answer:
When a solenoid is connected to a DC power supply and current flows through it, a magnetic field is produced. This magnetic field interacts with the small pile of iron paper-clips in the glass dish above the solenoid. However, since the metal bar used in this scenario is made of aluminum, it is not magnetic, and therefore the paper-clips will not be affected.
Step-by-step explanation:
When a solenoid is connected to a DC power supply and current flows through it, a magnetic field is produced. This magnetic field interacts with the small pile of iron paper-clips in the glass dish above the solenoid. Initially, when the power supply is switched on, the paper-clips will not be affected as the magnetic field is not strong enough to attract them. However, when the power supply is switched off, a change in the magnetic field occurs, creating a strong magnetic field that induces a current in the paper-clips. This induced current creates its own magnetic field which interacts with the magnetic field of the solenoid, causing the paper-clips to be attracted to the solenoid and jump up towards it.
However, since the metal bar used in this scenario is made of aluminum, it is not magnetic. Aluminum is a non-magnetic material, which means it cannot be magnetized or attracted to magnets. Therefore, the paper-clips will not be affected and will not exhibit any behavior when the procedure is carried out using an aluminum bar.