Electricity

The figure shows how electrical energy is transferred to a house from a power station.Which statement describes the role of the transformer?

• It stores the electrical energy for future use.
• It generates electrical energy.
• It converts the electrical energy to higher or lower voltages.
• It converts electrical energy to other forms of energy.

The image shows an electric energy production and transfer system.Three transformers are labeled in the image. Which statement can be true?

• ATransformer 1 will step up the voltage, and transformers 2 and 3 will step down the voltage.
• Transformers 1 and 2 will step up the voltage, and transformer 3 will step down the voltage.
• Transformer 3 will step up the voltage, and transformers 1 and 2 will step down the voltage.
• Transformers 2 and 3 will step up the voltage, and transformer 1 will step down the voltage.

Which term best  describes the device created when a wire in an electric current is wrapped around an iron core producing a magnetic field as a result?

• electromagnet
• generator
• insulator
• motor

Patrick is working with a corded drill. He observes that when he presses the trigger, the drill bit rotates and helps to drill a hole in the wall.Which energy transformation is taking place in this process?

• chemical energy to electrical energy
• electrical energy to chemical energy
• electrical energy to mechanical energy
• mechanical energy to electrical energy

Many homes in South Carolina are powered with electricity produced in nuclear power plants.Which device used in the production of electricity in the power plants produces the electricity to power the homes in South Carolina?

• battery
• electromagnet
• generator
• motor

Evan and Rachel each plugged in a strand of lights to test them before hanging them outside their house. Evan accidentally stepped on two of the lights, one on his strand and one on Rachel’s strand. Rachel noticed that even though Evan stepped on a light, her whole strand still lit, while Evan’s whole strand went dark.What is the difference between Evan and Rachel’s strands of lights?

• Rachel’s lights were organized in parallel, so as soon as one light broke, the total amount of energy in the strand increased, and the lights all stayed lit.
• Rachel’s lights were organized in series, so as soon as one light broke, the total amount of energy in the strand decreased, and the lights stayed lit.
• Evan’s lights were organized in parallel, so as soon as one light broke, the circuit was broken, and all the lights went out.
• 
  DEvan’s lights were organized in series, so as soon as one light broke, the circuit was broken, and all the lights went out.

What is a limiting factor in the transmission of electric current in power grids?

• The electric current cannot flow over long distances and therefore must be transformed, or stored, for later use.
• The electric current must be transmitted at low voltages and transformed to higher voltages for home use.
• The electric current requires a ground, and it is a difficult and time-consuming process to ground the electricity.
• The electric current must be transmitted at high voltages to avoid excessive resistance making transmission easier.

Which statement describes the flow of electric current in an AC circuit?

• It remains constant and unidirectional throughout the circuit.
• 
  It changes magnitude and direction with time.
• 
  It is converted into DC current at the outlet.
• It alternates between AC and DC current in a wire.

A student notices that every time the button for the doorbell is pressed, the doorbell rings. As soon as the button is released, the doorbell stops ringing.What kind of energy transformation takes place when the switch of the doorbell is pressed?

• electrical energy to sound energy
• mechanical energy to heat energy
• chemical energy to electrical energy
• electrical energy to chemical energy

The diagram shows a simple electrical circuit.What is happening at point X?

• 
  Electrons are moving through the circuit.
• Protons are moving through the circuit.
• 
  The flow of electrons through the circuit is stopped.
• The flow of protons through the circuit is stopped.