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

Answer 1

C

Closing the switch completes the circuit so current flows through the coil on the nail, turning it into an electromagnet. That lets the device pick up iron-containing (magnetic) items but not glass, plastic, or nonmagnetic metals like aluminum, so it separates iron-containing trash from other materials.