Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physics > Electricity and Static Electricity > Flashcards

Electricity and Static Electricity Flashcards

(45 cards)

Start Studying
1
Q

Current definition

A

Rate of flow of electric charge

ampere, A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Potential difference definition

A

how much energy is transferred between two points in a circuit
1V equivalent to 1J/C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

resistance definition

A

how much a component decreases the current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

charge definition

A

unit carrying electrical energy (Coulomb, C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why resistance increases with temperature

A

Electrons collide with ions in lattice they flow through
This causes them to vibrate and heat up
Transfers electrical energy to heat energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why resistance decreases current

A

More ions vibrate in the lattice the electrons go through, making it harder for the electrons to go through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Ammeter function

A

Measures current

Must be placed in series with component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Voltmeter function

A

Measures potential difference

Must be placed in parallel with component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Diode facts

A

Only lets current go in one direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thermistor facts

A

keeping supply potential difference constant gradually heats it
As temperature increases, current through thermistor increases (resistance decreases)
Useful in electronic thermostats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

LDR facts

A

light-dependent resistor
as light level near it increases, current increases as resistance decreases
Useful in automatic night lights and burglar detectors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

I-V graph of resistors and wires

A

Current is directly proportional to potential difference

Straight line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

I-V graph of filament lamp

A

Increasing current increases temperature of filament, so resistance increases, causing curve
S-shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

I-V graph of diode

A

Current is only allowed to flow in one direction
Diode has high resistance in opposite direction
Straight horizontal line then increasing curved line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Series circuit facts

A

All components must be connected or whole circuit fails
Components are connected end-to-end between +ve and -ve of power supply
Total potential difference is shared between components
Total resistance increases as more components increase
Current is the same everywhere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Parallel circuits facts

A

Each component is connected separately to +ve and -ve of power supply
Disconnecting one component hardly affects others at all
Potential difference is the same across all components
Current is shared between branches
Total current in is equal to total current out
Total resistance decreases as you add more components in parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Fuse function

A

Uses heat created by resistance in circuit to break the circuit when it gets too hot (current gets too high)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How filament bulbs, toasters and electric heaters work

A

Contains as coil of really high resistance

Causes lots of thermal energy to be emitted, causing a glowing effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Power definition

Study These Flashcards
A

How much energy is transferred per second

20
Q

How a higher power applicant transfers less energy than a lower power appliance

Study These Flashcards
A

Lower efficiency

21
Q

Power rating definition

Study These Flashcards
A

Maximum amount of energy transferred between stores per second when appliance is in use

22
Q

What power transferred by an appliance is reliant on

Study These Flashcards
A

Current

Potential difference

23
Q

Types of electrical supplies

Study These Flashcards
A 
Batteries (d.c.)
Mains supply (a.c.)
24
Q

Alternating current

Study These Flashcards
A

When the charges constantly change direction
Produced by alternating voltages (+ve and -ve ends keep alternating)
Frequency is 50Hz
UK mains supply is a.c. that supplies around 230V

25
Direct current
Movement of charged is only in one direction | Caused by direct voltage (negative or positive but never both)
26
Live wire facts
Brown | Carries voltage and alternating current of about 230V
27
Neutral wire facts
Blue Completes the circuit Electricity flows in through live wire and out through neutral wire Always 0V
28
Earth wire facts
Green and yellow For safety and protecting wiring Carries current away if something goes wrong and stops appliance from becoming live 0V
29
How plug sockets are made for safety
Plastic, non-conducting casing | Switches connected to live wire of circuit so circuit can be broken and risk of electric shock is reduced
30
Why touching a live wire gives you an electric shock
Body is at 0V If live wire is touched, large potential difference is produced across body and current flows through you Caused large electric shock which could kill you
31
Current surge causes
Changes in a circuit e.g. appliance switching off | Fault in an electrical appliance
32
Fuses method
Fault develops causing live wire touching the metal case Because case is earthed, this causes a current surge This melts fuse, isolating whole appliance from live wire Done so electric shock or a fire is impossible Fuses should be rated but just above normal operating current Larger current, thicker cable so cable doesn’t get too hot and melt
33
Circuit breakers method
Large current trips (turns off) a circuit breaker They turn off quicker than time taken for fuse to melt Can also be reset, more convenient than replacing a fuse Circuit breakers are more expensive than fuses
34
Double insulated appliances
Appliances with a plastic casing and no metal parts showing Don’t need an earth wire Connected to a two-core cable (only live and neutral)
35
How static is built up by friction
Insulating materials are rubbed together Negatively-charged electrons are scraped off one and dumped on the other Cannot move as sandwiched between insulators so they build up This gives both materials charge as both have lost or gained electrons
36
How electrically charged object (e.g. a balloon) can attract uncharged objects e.g. (a wall)
Attraction by induction Balloon is rubbed onto something to build static Its negative charges repel negative charges on surface of wall Leaves a positive charge on surface of wall, attracting balloon
37
How static causes sparks
Static builds up on an object If potential difference between that object and something else is large enough, electrons can jump across the gap between charged object and earth, causing a spark Only usually happens when gap is small
38
Static electricity used
Photocopiers Reducing dust and smoke from industrial chimneys Electrostatic sprayers
39
Electrostatic sprayers method
Spray gun is charged, charging up small drops of liquid Each drop of liquid repels the other, resulting in very fine spray Object may be given an opposite charge, attracting fine spray of liquid If not, objects become charged by induction, attracting drops of liquid
40
Static electricity danger in refuelling cars
Fuel flowing out of filler pipe can build up static | This can cause a spark, igniting fuel and causing an explosion
41
Static electricity dangers on airplanes
Friction between air and plane causes plane to become charged Static can the interfere with communication equipment
42
Static electricity dangers in lightning
Raindrops and ice bump together in storm cloud This leaves top of cloud positively-charged and bottom of cloud negative, creating huge potential difference Creates a spark (lightning), which can damage houses and start fires
43
Earthing definition and function
Connecting a charged object to the ground using a conductor Provides an easy route to the ground, so no charge is built up Electrons flow up from ground if charge is positive or vice verse if negative Fuel tankers must be earthed to prevent sparks causing fuel to explode
44
Electric field definition
region created by any electrically-charged object in which a force would be exerted on any charged objects placed within it
45
Electric field diagram rules
Closer to object, stronger field Field lines go from positive to negative Lines are right angle to surface of object Closer lines, stronger field

Physics (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions