Additional - Topic 2.1 - Static Electricity

Question 1

Explain what happens to the boy’s hair when it becomes positively charged.
(2)

Answer 1

An explanation linking one of the
following pairs
Either
• loss of a negative (1)
• electron (1)
Or
• hair’s repel (1)
• (because) like charges
repel (1)

Question 2

The boy puts his charged comb near some small pieces of paper.
Explain what happens.

Answer 2

An explanation linking three of
the following points
• paper is picked up (1)
• charged objects attract
uncharged (1)
• charges separate on paper
(1)
• opposite charges attract
(1)
• weight is less than
electrostatic force (1)

Question 3

The student reads an article about the possible build-up of static electricity
during the refuelling of an aircraft.
(i) Explain why this build-up could be dangerous.
(2)

Answer 3

An explanation linking any two
from
charges are separated (1)
possibility of a spark (1)
ignite the fuel (1)

Question 4

The article also states that the aircraft is connected by a metal cable to the ground.
The aircraft is also connected by a metal cable to the refuelling tanker.
Explain how these cables reduce the dangers when refuelling the aircraft.
(3)

Answer 4

An explanation linking three
from
Metals are (good) conductors (1)
Electrons/(negative) charge can
flow through wire (1)
charge goes from/to the ground /
earth (1)
discharge the tank/aircraft/pipes
(1)

Question 5

Explain the advantages of using an electrostatic insecticide spray compared to
an uncharged insecticide spray.
(3)

Answer 5

An explanation linking any three from
the following:
 Droplets have same charge (1)
 (droplets) repel (one another) (1)
 (This produces) a fine spray/mist
(1)
 attraction between droplets and
plant (1)
 This improves coverage OR Spray
covers whole [leaf /plant] top and
underside of leaf/ gives a fine
coating/ even coat (1)
 Less spray used/wasted/ falls onto
soil (so saves money)
(1)

Question 6

Plastic is an insulator.
A student rubs a piece of plastic with a cloth.
This gives the plastic a negative charge.
(i) Explain how the plastic is charged by the rubbing.
(2)

Answer 6

Correct responses can be seen in
(i) or (ii)
An explanation linking
• electrons (1)
and one of
• removed by friction (1)
• (transferred) to plastic (1)

Question 7

The cloth is also charged when it rubs against the plastic.
Describe the charge on the cloth.
(2)

Answer 7

opposite to charge on plastic
(1)
equal to charge on the plastic
(1)

Question 8

An electrostatic paint sprayer is about to be used to paint a metal object.
When the paint particles leave the sprayer, they are negatively charged.
Explain the benefits of using this sprayer compared with one that does not charge
the paint.
(6)

Answer 8

A description / comparison/ explanation / etc including some
of the following points
• paint particles have the same charge
• like charges repel
• Particles repel each other
• So spread out (more)/form a (fine) mist
• Even layers
• Improved finish
• Opposite charge(is induced) on object
• Paint particles are attracted to metal object
• To parts not in direct line of spray/back of object
• Need not move the sprayer to reach back
• Takes less time
• Uses less paint/ less paint wasted.
• Uncharged paint forms large droplets/runs (off object)
Allow reverse arguments for uncharged paint
Accept an explanation that includes the idea that there is
attraction between charged and uncharged/neutral/earthed
objects