Summary
Summary iGCSE Physics Pearson Edexcel Topic 2 Electricity Complete Notes
- Course
- Institution
iGCSE Physics Pearson Edexcel Topic 2 Electricity Complete Notes
[Show more]
Seller
Follow
anish24shah
Reviews received
Content preview
IGCSE PHYSICS – TOPIC 2ELECTRICITY
a) MAINS ELECTRICITY
• FUSES – a safety device designed to CUT OF FLOW of electricity to an
appliance if the current becomes too large sue to a fault/surge
o It is usually made from a glass cylinder and a thin metal wire:
o If the current becomes TOO LARGE the wire heats up and
melts which causes the circuit to break and the current to stop
o An RCD (circuit breaker) trips the switch
• EARTH WIRE – many electrical appliances have metal cases – safety
hazard. If a live wire came into contact with the case it would become
electrified – electrocution hazard - an earth wire reduces this risk
o In a plug there are 3 wires: neutral, live and earth:
o BLUE WIRE – kept at 0V – completes circuit – the neutral wire
o BROWN WIRE – carries 230V a.c. – the live wire
o YELLOW/GREEN – stops the appliance becoming live – the earth
wire
o The EARTH WIRE provides a low resistance path to the Earth – this
causes a SURGE OF CURRENT IN WIRE (earth and live) – the HIGH
CURRENT causes the fuse to break which cuts of the electricity to
the appliance – safe!
• DOUBLE INSULATION – some appliances have two layers of insulation –
insulation AROUND THE WIRE and a NON-METALLIC CASE as a second
layer – these appliances do not need an earth wire and are marked
with:
• Electricity in metals is caused by THE FLOW OF ELECTRONS – as the
electrons pass through the metal THEY COLLIDE WITH IONS – the ions
RESIST the flow of electrons:
11
, o When electrons collide they lose energy, giving it to the ions –
they START TO VIBRATE
o As a result the metal HEATS UP
o This effect is used in many electric heaters, ovens, electric hobs,
toasters and kettles
• Power is the RATE OF ENERGY TRANSFER:
Power (w) = Current x Voltage
P=IxV
• SELECTING FUSES – fuses come in a variety of sizes – 3A, 5A AND 13A
o In order to select the right one, you need to know the CURRENT
of the appliance (P = IV)
o The fuse should always have a HIGHER CURRENT than needed –
but not too high!
Energy Transferred (J) = Current x Voltage x Time or Power x Time
E = I x V x T or P x T
• ALTERNATING CURRENT – (a.c.) a current that changes direction
continuously (e.g. mains, generators)
• DIRECT CURRENT – (d.c.) a current that is steady and constantly flowing
from + -> - (e.g. batteries)
12
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anish24shah. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.75. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
78252 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now