Which material is a composite?(1 point)

Responses

polycarbonate
polycarbonate

gold
gold

aluminum
aluminum

silicon

What happens to some metals when the kinetic energy of their particles is decreased?(1 point)
Responses

They melt.
They melt.

They conduct.
They conduct.

They expand.
They expand.

They contract.

9 answers

They contract.
Which material is a composite?(1 point)
Responses

polycarbonate
polycarbonate

gold
gold

aluminum
aluminum

silicon
polycarbonate
Aluminum allows for the flow of electrons, while glass does not. Would an aluminum wire surrounded by glass be an effective design for a device that will need to carry an electric current?(1 point)
Responses

No, it would not. Both aluminum and glass are insulators, so the device would not carry a current.
No, it would not. Both aluminum and glass are insulators, so the device would not carry a current.

Yes, it would. The glass would carry the current, while aluminum is an insulator.
Yes, it would. The glass would carry the current, while aluminum is an insulator.

Yes, it would. Aluminum is a conductor, and the glass would prevent electricity from transferring to a person holding the device.
Yes, it would. Aluminum is a conductor, and the glass would prevent electricity from transferring to a person holding the device.

No, it would not. Both aluminum and glass are conductors, so the current would be exposed to outside elements.
No, it would not. Both aluminum and glass are insulators, so the device would not carry a current.
Which material would be a suitable insulator?(1 point)
Responses

gold
gold

rubber
rubber

copper
copper

silver
silver
rubber
An electrician is trying to decide which kind of material to use to wire a house.

carbon steel: conductivity = 1.43 × 10−7, resistance = 1 × 1010
copper: conductivity = 5.96 × 107, resistance = 1.68 × 10-8
gold: conductivity = 4.11 × 107, resistance = 2.44 × 10−8
iron: conductivity = 1 × 107, resistance = 1.0 × 10−7
Based on this information, which material should the electrician use?

(1 point)
Responses

iron
iron

carbon steel
carbon steel

copper
copper

gold
Copper