ELECTRICITY, CURRENT, VOLTAGE AND RESISTANCE

ELECTRICITY, CURRENT, VOLTAGE AND RESISTANCE

by KASMAWATI Moe

​Learning outcomes

​By the end of the lesson, students should be able to

1. ​Describe and explain static electricity

2. Explain electric force

3. Describe conductors and insulators

4. Understand electric current in a circuit

5. Discuss and construct components in parallel circuit

Let's recall last lesson.

• Static electricity is the buildup of electric charges.

• Opposite charges attract; like charges repel.

• Positively charged atoms have more protons

• negatively charged atoms have more electrons.

electric currents

Multiple Choice

The electrician in this picture is wearing rubber gloves for protection.  The purpose of the rubber gloves is to --

• keep the electrician dry
• create an electrical circuit
• produce electricity
• protect the electrician

Multiple Choice

Which of these substances conducts electricity the best?

• wood
• brick
• copper
• plastic

Multiple Choice

What material would be safest to use as an insulator to cover electrical wires?

• rubber
• tin
• aluminum
• water

During a lightning...

• Electrons in the atmosphere jump down to pair with protons on the ground.

Key terms:

• Electric current: flow of electric charge through a conductor

• direct current: current in which electrons always flow in the same direction

• alternating current: current in which electrons constantly change directions at a regular rate.

What is an electric current?

The flow of electric charges through a conductor.

Multiple Choice

Lightning is an example of _________.

• static electricity
• current electricity
• watts
• voltage

Multiple Choice

What supplies the energy in an electric circuit?

• light bulb
• conductor
• wire
• battery

The difference between static electricity and electric currents.

Electric charges that build up on static electricity do not flow. Instead the charges jump between two objects.

electric currents is a flow of electrons like a stream of water through a conductor like copper or metal.

Open Ended

What is the difference between static electricity and electric current?

What is a direct current?

• An electric current in which charges flow in one directly only.

• The current produces by electrochemical cells is direct current. The chemical energy is being changed into electrical energy.

• When the switch is on the electric current produced by the dry cells keeps the light bulb on

Alternating current:

• type of current that does not flow in one direction only.

• constantly changes direction at a regular rate.

• can be transported more easily over long distance

Open Ended

you have 15 minutes to answer this question on this slide. Describe the difference in the flow of DC and AC currents from the video clip

Open Ended

What is a direct current?

alternating current

alternating current can be changed to direct current. In the home, many electronic devices such as computers, televisions, sets, and CD players use direct current. Converters built into these devices converts alternating currents to direct currents.

Open Ended

What is alternating current? (15 minutes to type in your answer)

Multiple Choice

Current that reverses direction at a regular rate is called _______ current.

• electrical current

• direct current

• alternating current

Multiple Choice

Most of the electricity that is used in your home and at school comes from _____ current.

• direct current

• alternating current

Multiple Choice

The type of electric current supplied by power plants is _______ current.

• direct current

• alternating current

Electricity through a bulb

A bulb will only work if it you connect the wires/conductors correctly to its terminals.

One end of the circuit must be connected to the TIP of the bulb, and the other end to the metal case of the bulb.

Multiple Choice

The flow of electric charges through a conductor is called

• electric current

• direct current

• alternating current

Multiple Choice

What word means how fast the electrons flow.

• Current
• Voltage
• Resistance
• Power

Multiple Choice

What is Resistance?

• The flow of electrons
• Electric potential difference
• A battery
• The ability to reduce the flow of electrons

Multiple Choice

What is resistance measured in?

• Ω (Ohms)
• V (Volts)
• A (Amps)
• W (Watts)

Multiple Choice

The mathematical relationship among Voltage, Current, and Resistance

• Faraday's Law
• Tesla's Law
• Edison's Law
• Ohm's Law

Multiple Choice

What is the formula for ohms law?

• 1+2=3

• R X E = I

• V =I x R

• E= MC squared

Multiple Choice

What is the Voltage of a circuit that has a resistance of 5 Ω and a current of 2 A?

• 25 V
• 10 V
• 2.5 V
• 0.4 V

Multiple Choice

What resistance is needed to cause a 50A current flow because of a 500V battery?

• 10Ώ
• 5Ώ
• 2500Ώ
• 550Ώ

Multiple Choice

What voltage is needed to cause a 2A current flow through a 10Ω resistor?

• 5V
• 0.2V
• 20V
• 200V

Multiple Choice

What size resistor would produce a 3 Amp current flow with a 12 Volt battery

• 1 Ohm
• 3 Ohms
• 4 Ohms
• 12 Ohms

Multiple Choice

What is the resistance of a lightbulb that experiences 9 Volts and 3 amps of current?

• 1/3 ohms

• 3 ohms

• 27 ohms

• 9 ohms

​Voltage, Current, Resistence

​V = Voltage

​I = Current

​R = Resistance

​Current and Voltage

​Is DIRECTLY PROPORTIONAL. When current increases the voltage also increases. And vice versa.

The higher the voltage needed of a device the higher its power consumption

Multiple Choice

Voltage is measured in __.

• volts.
• watts.
• coulombs. 

Multiple Choice

Current has units: 

• kilowatt·hour 
• ampere 
• coulomb 
• volt 

Multiple Choice

As the resistance of a circuit increases, the current will

• increase
• decrease
• stay the same

Multiple Choice

What 'flows' in a wire?

• Protons
• Neutrons
• Atoms
• Electrons