Flow of Electricity

Flow of Electricity

Static Electricity

• Caused by the imbalance of charges on the surface of an object

Multiple Choice

A glass rod is rubbed with a cloth. Which diagram shows how the rod becomes negatively-charged?

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

A polythene rod repels an inflated balloon hanging from a nylon thread.

Why do the rod and balloon repel?

• The rod and the balloon have opposite charges.

• The rod and the balloon have like charges.

• The rod is charged but the balloon is not.

• The balloon is charged but the rod is not.

Electrical Circuits

• Battery provides energy for the electric current to flow

• Wires provide a complete conductive path for the current

• Switch opens or closes the circuit

• Electrical load consumes electricity and converts it to other forms of energy

Multiple Choice

Which symbol is used to represent a resistor in a circuit?

Multiple Choice

What refers to the rate of flow of charge?

• Current

• Potential Difference

• Power

• Resistance

Multiple Choice

The diagrams below show circuits with identical bulbs and batteries of 1.5 V each. Which circuit has a bulb that does not light up?

• A

• B

• C

• D

Multiple Choice

A person inserted a metal knife inside a plugged-in toaster.

Which best explains why the person is at risk of electrocution?

• The knife provides a surface for charges to build up on.

• The knife provides an alternative low resistance path for the current.

• The knife provides an alternative high resistance path for the current.

• The knife provides more energy to push the charges through the circuit.

Ohm's Law

• V and I are directly proportional, keeping R constant

• V and R directly proportional, keeping I constant

• I and R inversely proportional, keeping V constant

Multiple Choice

Which circuit will have a current of 0.9 A?

Multiple Choice

What is the resistance of the bulb in this circuit?

• $$0.03\ \Omega$$
  

• $$3\ \Omega$$

• $$30\ \Omega$$

• $$300\ \Omega$$

Multiple Choice

Ana plugged in a 110V-rated device in a 220V outlet and it overheated.

What explains the overheating?

• The device took in more amperes than it can normally handle.

• The device provided too much resistance to the electrical circuit.

• The device did not take in as much amperes as it normally would.

• The overall resistance of the electrical circuit was significantly reduced.

Multiple Choice

Which switch on the diagram below would turn off all lights when opened?

• A

• B

• C

• D

Series and Parallel Circuits

• Adding more resistors in series increases the total resistance in a circuit

• Adding more resistors in parallel branches decreases the total resistance

Multiple Choice

The diagram below shows resistors connected in different ways. Rank the three ways according to increasing resistance.

• 1 < 2 < 3

• 2 < 1 < 3

• 2 < 3 < 1

• 3 < 1 < 2

Multiple Choice

A circuit contains a lamp. Which change will increase the current through the bulb?

• using a battery with a lower voltage

• moving the lamp to point P in the circuit

• adding an identical resistor in series with the one in the circuit

• adding an identical resistor parallel to the one in the circuit

Multiple Choice

Why are lamps in a house lighting circuit connected in parallel rather than in series?

• If one lamp stops working, the remaining lamps become brighter.

• Less current is taken from the power supply.

• The lamps can be turned off independently using switches.

• When more lamps are added, their brightness decreases.

Multiple Choice

• X

• Y

• Z

• All ammeters have the same reading.