electricity

Question 1

electrical hazards

Answer 1

• water in contact with something
• electrical device reaches high temp
• damaged equipment
• overloaded cables/sockets
• cables cause trip hazards

Question 2

how does an earth wire work

Answer 2

provides a low resistance path for current so causes a large surge in earth and fuse breaks

Question 3

what effect does resistant wires have on current

Answer 3

• causes electrical transfer
• due to electrons colliding with metal ions in wire
• heats up the wire

Question 4

what colour is the live wire

Answer 4

brown

Question 5

what colour is the neutral wire

Answer 5

blue

Question 6

what colour is safety wire

Answer 6

yellow and green

Question 7

difference between AC and DC

Answer 7

AC: alternating direction
DC: direct direction

Question 8

what does short thick copper wire graph look like

Answer 8

steep diagonal line through the origin

Question 9

what does filament lamp graph look like

Answer 9

curved line through the origin

Question 10

what does long thin copper wire graph look like

Answer 10

not steep diagonal line through origin

Question 11

what does diode graph look like

Answer 11

diagonal line starting half way on the x axis

Question 12

how does resistance in a LDR differ

Answer 12

BRIGHT LIGHT = low resistance
vice versa
inversely proportional relationship

Question 13

advantages of series circuit

Answer 13

• fewer wires
• lower resistance value

Question 14

disadvantages of series circuit

Answer 14

• one component fails, all fail
• no independent control

Question 15

advantages of parallel circuit

Answer 15

• independent control
• circuit doesn’t fail if one breaks

Question 16

disadvantages of parallel circuit

Answer 16

• lots of wires
• higher resistance value

Question 17

what is more appropriate for lighting in a house

Answer 17

parallel circuits

Question 18

how to show a plastic rod gains charge

Answer 18

• deflects water stream
• gold leaf electroscope

Question 19

how to demonstrate charges with plastics

Answer 19

• charge rods of 2 diff plastics
• allow to swing freely
• observe repulsion or attraction

Question 20

how does a plane become electrically charged

Answer 20

friction between aircraft and air
causes electron transfer

Question 21

why would someone receive a shock from metal if it is earthed

Answer 21

• it still conducts electricity
• current flows through the person
• so electrons can transfer from the metal to the person

Question 22

Which type of rod becomes negatively charged when rubbed with cloth?

Answer 22

• Polythene
  (remember polythene is mean and takes all the electrons)

Question 23

Which type of rod becomes positively charged when rubbed?

Answer 23

• Acetate
  (remember acetate is great and gives away its electrons)

Question 24

Potential dangers of fueling an aircraft

Answer 24

• Aircraft becomes charged during flight
• touching it could cause a spark
• the introduction of fuel can cause a fire/explosion

Question 25

What is charge measured in

Answer 25

Coulombs (C)

Question 26

What is ‘earthing’ and what are the benefits?

Answer 26

• Earthing is offering an alternate pathway, with lower resistance, to the Earth
• Causes charged objects to be discharged and reduces the risk of shock

Question 27

Uses of electrostatic charges

Answer 27

• Paint sprayer
• photocopier

Question 28

How does an electrostatic paint sprayer work?

Answer 28

• All paint is given same charge- pellets spread out more causing greater coverage of paint
• Object being painted given opposite charge to make paint attract to object
• Less paint wasted