P4

HideShow resource information
1. What happens when two materials are rubbed together?
Electrons travel from one material to the other leaving one postively and one negatively charged item.
1 of 23
2. How can you get an electrostatic shock from synthetic clothing?
Friction between the clothing and the person's body can sometimes cause a static spark.
2 of 23
3. How can you get an electric shock if you become charged then earthed?
When an object is discharged it looses electrons from the object to the earth. This can cause a electrostatic shock.
3 of 23
4. Understand that: Like charges .......... and opposite charges ...........
Like charges repel and opposite charges attract.
4 of 23
5. What is the elctrostatic phenomena caused by?
Transfer of electrons.
5 of 23
6. How is static electricity dangerous?
In flour mills it has a atmosphere that can contain extremely flammable gases or high concentrations of oxygen. A discharge of static electricity (spark) can lead to an explosion. Also when large amounts flow through your body to earth like lightning
6 of 23
7. How can static electricity be a nuisance?
Dirt and dust is attracted to insulating materials and some materials cling to your skin.
7 of 23
8. How can electric shocks be reduced?
Correctly earthing appliances, use insulating mats effectively and wear shoes with insulating soles. Lorries need to be deearthed before unloading to reduce sparks. Anti-static sprays prevent the transfer of charge.
8 of 23
9. Explain electrostatic precipitators.
Remove dust from chimneys. Metal grids installed in chimney and connected to a high voltage. Dust becomes positively charged and attracted to negative plates. These form big dust particles and fall back down the chimney.
9 of 23
10. How are electrostatic sprays used?
Nozzle of the gun is negatively charged. When the paint particles go through they get a negative charge so they repel each other forming a spray. Paint is even. Panel sprayed is positive. Less paint is wasted and all places on the car receive paint.
10 of 23
11. How is static electricity used in defibrillators?
Two paddles are charged and are put in good electrical contact with the patients chest. Charge is passed through to make the heart contract.
11 of 23
12. What is a circuit?
Complete loop that allows an electrical current to flow. A current is a flow of electrons from the negative electrode to the positive electrode.
12 of 23
13. How resistors can be used to change the current in a circuit?
Fixed resistor: constant resistance. Bigger the resistance smaller the current. Variable resistor have a changeable resistance.
13 of 23
14. Longer and thinner wires give ........... resistance and lower current.
More
14 of 23
15. Recall the colour coding for live, neutral and earth wires.
live–brown • neutral–blue • earth–green/yellow. An earthed conductor cannot become live.
15 of 23
16. What is the use of fuses and circuit breakers?
Safety features that break a circuit if a fault occurs. Could prevent fires, deaths or injuries.
16 of 23
17. What is a fuse? What is a circuit breaker?
Short thin piece of wire with a low melting point. This means it can melt if the temperature becomes too high and it will break the circuit. Circuit breakers are like fuses but they can be reset rather than replaced.
17 of 23
18. Why do double insulated items not need earthing?
The appliance is a non-conductor and cannot become live.
18 of 23
19. Give the equation for resistance.
Resistance = Voltage/Current
19 of 23
20. What are the functions of the different types of wires?
live–carries the high voltage • neutral–completes the circuit • earth–a safety wire to stop the appliance becoming live.
20 of 23
21. Give the equation for power.
Voltage x Current
21 of 23
22. Describe the relationship between voltage, resistance and current.
Current increases as voltage increases. Current decreases as resistance increases.
22 of 23
23. Describe the features of a longitudinal wave.
Areas of rarefraction and compression.
23 of 23

Other cards in this set

Card 2

Front

2. How can you get an electrostatic shock from synthetic clothing?

Back

Friction between the clothing and the person's body can sometimes cause a static spark.

Card 3

Front

3. How can you get an electric shock if you become charged then earthed?

Back

Preview of the front of card 3

Card 4

Front

4. Understand that: Like charges .......... and opposite charges ...........

Back

Preview of the front of card 4

Card 5

Front

5. What is the elctrostatic phenomena caused by?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Radiation for Life resources »