From the experiment set up in the diagram, the pointer is resting on the drinking straw while the rod is resting on the drinking straw.
When the rod is being heated through the bursen burner, there will be linear expansion in the rod. As the rod increases its length, this causes the drinking straw to roll and thereby causing the pointer to rotate.
The pointer therefore rotates because of the thermer expansion that happen in the rod due to the heat from the bursen burner.
Electromagnet refers to an iron ore wrapped around with a coil of wire, in presence of electric current. As it acts like a magnet, when current is passed through it.
The north & south poles of magnetic fields produced by such magnet, change with direction of current passed through it.
For an individual ( not a repair station) to conduct a complete 100 hour inspection on an aircraft and approve it for return to service requires a mechanic certificate with and powerplant and airframe ratings
Explanation:
Because these are important certificates issued by the FAA giving the mechanic authority to inspect to inspect an aircraft and approve its return to services