PS, CH6-Electricity, TEST

The negatively charged particles in an atom are called _______________________________.

• neutrons
• negatrons
• protons
• electrons

Positive charges flow from _________________________?

• low-voltage areas to high-voltage areas
• high-voltage areas to low-voltage areas
• insulators to conductors
• low-resistance areas to high-resistance areas

Which of these is necessary in order to make an electric circuit?

• a light bulb
• copper wire
• a battery
• a closed path

Resistance is the tendency of a material to oppose the flow of electrons.

• True
• False

Electrical devices have resistance because they ______________?

• convert some thermal energy into electrical energy
• are exposed to sunlight
• convert some electrical energy into thermal energy
• contain insulators

Voltage difference is measured in _____________?

• watts
• volts
• amps
• ohms

What device has a small wire that melts if the current is too high?

• circuit breaker
• fuse
• switch
• dry cell

Which of these two materials are good conductors?

• wood and plastic
• water and glass
• water and rubber
• copper and water

Which of the following is a device designed to open an overloaded circuit, prevent overheating and automatically stop electrical current from flowing?

• circuit breaker
• magnet
• resistor
• fuse

Electrical wires sometimes have a plastic coating which makes them safer to handle because:

• plastic will melt if the wires overheat
• plastic is smooth and not easily frayed
• plastic is a good insulator
• plastic does not react chemically with air