5.2 resistance

Goals
5.2.1 You can explain how to determine the resistance of a wire or other component.
5.2.2 You can do calculations using the relationship between resistance, voltage and current.
5.2.3 You can explain the difference between ohmic and non-ohmic resistance.
5.2.4 You can describe how the resistance of an NTC or LDR depends on other variables.

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Slide 1: Tekstslide
NatuurkundeMiddelbare schoolhavoLeerjaar 3

In deze les zitten 14 slides, met interactieve quizzen en tekstslides.

time-iconLesduur is: 45 min

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Goals
5.2.1 You can explain how to determine the resistance of a wire or other component.
5.2.2 You can do calculations using the relationship between resistance, voltage and current.
5.2.3 You can explain the difference between ohmic and non-ohmic resistance.
5.2.4 You can describe how the resistance of an NTC or LDR depends on other variables.

Slide 1 - Tekstslide

resistance
The property of a component that determines how easily electrical current flows through it.

Slide 2 - Tekstslide

Slide 3 - Tekstslide

Ohm’s Law
The rule that says the voltage (across the wire) and the current (through the wire) are directly proportional.

Slide 4 - Tekstslide

A current of 20 mA runs through a 600 Ω resistor.

What is the voltage across the resistor?

Slide 5 - Open vraag

Resistor
George Ohm

Slide 6 - Tekstslide

ohmic resistance
Resistor where the resistance is the same regardless of the voltage.

Slide 7 - Tekstslide

There is a voltage of 12 V across a resistor. A current of 30 mA goes through the resistor. Ohm’s law applies to this resistor.

What current would go through the resistor when the voltage is increased to 36 V?

Slide 8 - Open vraag

Beth is doing a series of measurements on two wires (A and B). She has made an (I,U) diagram of her measurements.

Which wire has the higher resistance?
A
Wire A
B
Wire B
C
Impossible to say

Slide 9 - Quizvraag

The resistance of a lightbulb, 
ohms law does not apply
incandescent bulb

Slide 10 - Tekstslide

Here are the (I,U) diagrams of three resistors.

Which resistor obeys Ohm’s law?
A
Resistor A
B
Resistor B
C
Resistor C

Slide 11 - Quizvraag

NTC
A variable resistor that changes to the amount of themperature 
 (higher resistance when the temperature is lower)

Slide 12 - Tekstslide

LDR
A variable resistor that is sensitive to changes in the amount of light.
(higher resistance when the light is lower)

Slide 13 - Tekstslide

The resistance of an NTC is related to the temperature.

Which of the graphs correctly represents this relationship?
A
Graph A
B
Graph B
C
Graph C
D
Graph D

Slide 14 - Quizvraag