Question

Nimon and his team are designing a system to process and sort trash at a recycling plant. They build a model of a device that will be part of the system. Then, they test the model on different types of marbles, as shown in the diagram.

diagram%20showing%20an%20electrical%20wire%20wrapped%20around%20a%20nail%20and%20attached%20to%20a%20switch%20and%20a%20battery.%20Plastic%2C%20glass%2C%20and%20steel%20marbles%20are%20shown%20near%20the%20device.
Notice the switch in the model. Activating the switch is most useful for meeting which of the team's project criteria?

A.
Pieces of trash must be separated according to their size and shape.
B.
Trash that contains iron must be separated from aluminum and other metals.
C.
Iron-containing trash must be lifted from one place and dropped elsewhere.
D.
Pieces of metal trash must be separated according to their mass.

Answer 1

B. Turning the switch completes the circuit and makes the nail an electromagnet, so it will attract iron/steel objects but not non‑magnetic materials like plastic, glass, or aluminum — letting them be separated.