Resistance

joe saffer
Note by , created almost 6 years ago

Cambridge IGCSE Physics (electricity) Note on Resistance, created by joe saffer on 05/07/2013.

Eye 94
Pin 2
Balloon left 0
Tags
joe saffer
Created by joe saffer almost 6 years ago
Forces & Fields
Salma Mob
Energy and Electricity Quiz (Section 1 on Revision Checklist)
Alex Rizvi
Circuit Symbols
Freya Bolton
GCSE REVISION TIMETABLE
gracemiddleton
GCSE Core Chemistry Yr 9
bronwyn831
GCSE AQA Physics Unit 2 Flashcards
Gabi Germain
AQA GCSE Physics Unit 2
Gabi Germain
Physics equations GCSE
Mia Jones
P1 12/6/2015 (pm)
I M Wilson
LEARN IT 2: Electricity
Isleworth Physics

Page 1

Resistance

Resistance is measured in ohms (Ω)  Resistors are used to reduce the current in a circuit Total resistance in series Rt=R1+R2+R3 ......... Total resistance in parallel 1/Rt = 1/R1 +1/R2 + 1/R3 ..........

find the total resistance ----5Ω-----------7Ω-----------5 + 7 = 13and = 13Ω

find the total resistance---------4Ω-|-----8Ω-|---|--6Ω---------|                 |---5Ω---|   |-- 3Ω--3Ω--|

1/Rt = 5/40+8/401/Rt = 13/40Rt    = 40/13Rt    = 3 

1/Rt = 1/6+1/61/Rt = 2/6Rt    = 3

Rt = 4+3+3Rt = 10

Resistance of a wire

Electrons collide with and are repelled by ions More collisions = lower current and higher resistance thicker wire = lower resistance  (more room of electrons) longer wire = higher resistance (more ions)

Resistance

Resistance of a wire