Lesson 11

Electricity — Ohm's Law

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Slide 1: Slide

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This lesson contains 18 slides, with text slides and 1 video.

Lesson duration is: 45 min

Items in this lesson

Electricity — Ohm's Law

Slide 1 - Slide

This lesson

Properly understanding voltage
Ohm's law
Practice exercise (the homework)
Worksheet Ohm's law

Slide 2 - Slide

Learning goals

You can explain what current, resistance and voltage are in your own words and name the correct unit for each.

You can name Ohm's law in words and in symbols and you can do calculations with it.

You are able to rearrange Ohm's law.

Slide 3 - Slide

Current, voltage and resistance.

Current: the flow of charged particles from one point in a circuit to another. Expressed in amperes (Coulomb / second)

Voltage: The difference in electrical potential energy between two points in a circuit. Expressed in volts (Joules / coulomb)

Resistance: The opposition to the flow of charged particles. Expressed in Ohms.

Slide 4 - Slide

Slide 5 - Slide

Circuit lab

Ohm's law

Slide 6 - Slide

Current, voltage and resistance.

Current: the flow of charged particles from one point in a circuit to another. Expressed in amperes (Coulomb / second)

Voltage: The difference in electrical potential energy between two points in a circuit. Expressed in volts (Joules / second)

Resistance: The opposition to the flow of charged particles. Expressed in Ohms.

Slide 7 - Slide

Slide 8 - Video

Ohm's law

C u r r e n t = \frac{​ V o l t a g e ​ ​}{​ R e s i s t a n c e ​}

I = \frac{​ V ​ ​}{​ R ​}

Physical quantity

Current (I)
Voltage (V)
Resistance (R)

Current: the flow of charged particles from one point in a circuit to another. Expressed in amperes (Coulomb / second)

Voltage: The difference in electrical potential energy between two points in a circuit. Expressed in volts (Joules / second)

Resistance: The opposition to the flow of charged particles. Expressed in Ohms.

Unit

CAmpere (A)
Volt (V)
Ohm (Ω)

Slide 9 - Slide

3 lamps are connected to a battery in a parallel circuit. The battery supplies the circuit with 2.4 Ampere.

Because of its resistance, the second lamp gets 2/3 of the current supplied to the circuit. The rest of the current gets divided evenly over the other two lamps.

The voltage over the battery is 6 Volts.

Calculate the resistance of each lamp.

Slide 10 - Slide

R = \frac{​ V ​ ​}{​ I ​}

V = I \cdot R

I = \frac{​ V ​ ​}{​ R ​}

C u r r e n t = \frac{​ v o l t a g e ​ ​}{​ r e s i s t a n c e ​}

V o l t a g e = c u r r e n \cdot r e s i s t a n c e

R e s i s t a n c e = \frac{​ V o l t a g e ​ ​}{​ c u r r e n t ​}

Rearrange the formula

In words

In symbols

Slide 11 - Slide

R = \frac{​ V ​ ​}{​ I ​}

V = I \cdot R

I = \frac{​ V ​ ​}{​ R ​}

C u r r e n t = \frac{​ v o l t a g e ​ ​}{​ r e s i s t a n c e ​}

V o l t a g e = c u r r e n \cdot r e s i s t a n c e

R e s i s t a n c e = \frac{​ V o l t a g e ​ ​}{​ c u r r e n t ​}

Rearrange the formula

In words

In symbols

Slide 12 - Slide

R = \frac{​ V ​ ​}{​ I ​}

V = I \cdot R

I = \frac{​ V ​ ​}{​ R ​}

C u r r e n t = \frac{​ v o l t a g e ​ ​}{​ r e s i s t a n c e ​}

V o l t a g e = c u r r e n \cdot r e s i s t a n c e

R e s i s t a n c e = \frac{​ V o l t a g e ​ ​}{​ c u r r e n t ​}

Rearrange the formula

In words

In symbols

Slide 13 - Slide

R = \frac{​ V ​ ​}{​ I ​}

V = I \cdot R

I = \frac{​ V ​ ​}{​ R ​}

C u r r e n t = \frac{​ v o l t a g e ​ ​}{​ r e s i s t a n c e ​}

V o l t a g e = c u r r e n \cdot r e s i s t a n c e

R e s i s t a n c e = \frac{​ V o l t a g e ​ ​}{​ c u r r e n t ​}

Rearrange the formula

In words

In symbols

Slide 14 - Slide

R = \frac{​ V ​ ​}{​ I ​}

V = I \cdot R

I = \frac{​ V ​ ​}{​ R ​}

C u r r e n t = \frac{​ v o l t a g e ​ ​}{​ r e s i s t a n c e ​}

V o l t a g e = c u r r e n \cdot r e s i s t a n c e

R e s i s t a n c e = \frac{​ V o l t a g e ​ ​}{​ c u r r e n t ​}

Rearrange the formula

In words

In symbols

Slide 15 - Slide

Practice exercise

A) An average refrigerator works on a voltage of 120 Volts. A normal resistance for a refrigerator can be 45 Ohm. Calculate the current flowing through a refrigerator that has these properties.

B) What would the resistance on a fridge that has the same voltage have to be if it has a current of 2.4 Ampere flowing through it?

Slide 16 - Slide

Worksheet Ohm's law

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Learning goals

You can explain what current, resistance and voltage are in your own words and name the correct unit for each.

You can name Ohm's law in words and in symbols and you can do calculations with it.

You are able to rearrange Ohm's law.

Slide 18 - Slide

Lesson 11

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