5.2 current and voltage

Brainiac http://www.youtube.com/watch?v=-n1pSHzdahc

5.2 Current and Voltage12 April 2023

What are the key words to do with

‘electricity’? Can you define them?

Aims

• State the equations of current and voltage in a series circuit

• Describe the changes in current and voltage in a series circuit

• Define current and voltage

Current

Wh

at if

we

app

ly t

he

bra

kes?

For a series circuit:

321 IIII

The current is the same throughout the circuit

Current is the rate of flow of charge

t

QI

Current

The number of Coulombs flowing past a point in the circuit every second.

I = Q/t

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A

I’m counting how many

coulombs of electrons go

past me every second

1 Amp = 1 coulomb per second

Voltage

For a series circuit:

321 VVVV

The total voltage is the sum of the individual voltages

Voltage(emf)☺

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☺V

I’m checking the difference in energy (per

coulomb) between the 2 red arrows

1 Volt = 1 Joule per coulomb

Voltage (p.d.)☺

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V

I’m checking the difference in energy (per

coulomb) before and after the lamp

1 Volt = 1 Joule per coulomb

Voltage is the energy transferred per charge

Q

WV