Lesson 4 — Current, voltage and ressistance

• Physics
• Middelbare school
• vwo
• Leerjaar 3

Electricity — 5.2 Resistance

This lesson

• The planner
  
• Discussing the homework
  
• Voltage, current & resistance
  
• Going over 5.2 Resistance
  

Discussing the homework

Exercise 2

Variable	Symbol	Unit	Symbol
voltage
	I
		Ohm

Exercise 2

Variable	Symbol	Unit	Symbol
voltage	U	Volt	v
Current	I	Ampere	A
Resistance	R	Ohm	Ω

Excercise 4

a) The current changed

b) 

c) The wire heated up

d)

$$R=\frac{U}{I}$$

Excercise 4

a) The voltage remains constant, but the current changed over time. This can only be the case when the resistance of the filament changes.

b) 

c) The wire inside of the incandescent bulb 

heated up which caused the resistance to increase.

d) 

$$R=\frac{U}{I}$$

Current

Voltage

Resistance

$$R=\frac{U}{I}$$

$$Resistance=\frac{voltage}{current}$$

Current — The amount of charge that flows through a given point in a circuit per unit of time.

Voltage — The difference in electrical potential energy between two points in a circuit.

Resistance — The measure in which a circuit resists the flow of electrical current.

Going over 5.2

Resistance, voltage & current

• Understand the concepts theoretically
• Understand what they are in an electric circuit

Ohmic resistance

Resistance and temperature

Variable resistors

Homework

Read 5,2 Plus section

> 5.2 Exercise 10, 11

< 5.2 Exercise 10