Chapter 13: Electrical Systems

Which statement best describes current?

• Amount of energy needed to drive one unit charge around the circuit per unit time

• Rate of flow of electric charges per unit time

• Amount of electrical energy converted to other forms of energy per second

• Hindrance to the flow of charges

What is the SI unit of power?

• Ampere

• Volt

• Ohm

• Watt

Draw the circuit symbol of a variable resistor.

Answer explanation

What effect of electrical current is shown in the image here?

• Heating

• Magnetic

• Chemical

• Lighting

An electric iron has a power rating of 10W. This means that ___J of electrical energy is converted to other energy forms in one second.

Draw the circuit symbol of a fixed resistor.

Answer explanation

Which statement about conductors is true?

• it is hard for electric current to flow

• plastic is a good conductor of electricity

• conductors have high resistance

• electric current can flow easily

When does a circuit breaker trip to protect the user from electric shock?

• when the circuit becomes too hot

• when the electric current is too high

• when there is too much resistance

Which statement about fuses is true? (Hint: There are 2 correct answers!)

• Fuses do not need to be replaced when they blow.

• They contain thick wires that melt easily when voltage is too high.

• They contain thin wires that melt easily when current is high.

• Fuses need to be replaced when they blow.

Add an instrument to measure current in the circuit below.

Answer explanation

ammeter is used to measure current in a circuit. it is connected in series to a circuit.