Electrostatics

Question 1

what allows electrons to escape an atom?

Answer 1

heat energy

Question 2

if electrons leave an atom what does it become?

Answer 2

a positive ion

Question 3

when does charging by friction occur?

Answer 3

when friction between two solid insulating surfaces provides the energy to move electrons from one object to another

Question 4

what are the two rules of electrostatics?

Answer 4

1. like charges experience repulsive forces

2. unlike charges experience attractive forces

Question 5

why does a balloon become negatively charged when you rub it on your jumper?

Answer 5

it is charged by friction
the electrons from the jumper transfer to the balloon
jumper becomes positive
balloon becomes negative

Question 6

why will a negatively charged balloon stick to a wall?

Answer 6

the negative balloon will repel the electrons in the wall

the induced positive charged will attract the negative balloon

Question 7

what is charging by induction?

Answer 7

when a charged object (ie the negative balloon) repels the like charges in another object it will become charged

Question 8

how do ink jet printers work?

Answer 8

ink droplets are charged by friction as they leave the nozzle of the cartridge
as they pass through an electric field they experience a force
by varying the strength of the field the dots can be steered to form

Question 9

how does spray painting car bodies work?

Answer 9

the spray paint becomes charged (say negative) as it leaves the nozzle
the like-charged atoms repel each other so the paint comes out in a fine mist
the car body is charged in advance (say positive) so the oppositely charged paint is attracted to it and sticks

Question 10

how do electrostatic precipitators work?

Answer 10

smoke rises through a chimney
the smoke passes through a positively charged grill so the electrons are removed from it
there is negatively-charged lining in the chimney
the smoke is attracted to the lining, meaning particles are pulled out of it
when the smoke leaves it has fewer particles

Question 11

what are two hazards of electrostatics and how are they combated?

Answer 11

1. refueling aircraft
   when fuel is pumped through a pipe it is charged by friction
   the fuel tank contains lots of charged fuel
   the charge will jump to the ground, which will cause a spark and ignite the fuel
2. electronic components
   things like microchips can be damaged by high voltages caused when things charge up

both can be combated with an earth wire to pull the charge to the ground