Uses Of Electrostatics

Question 1

Recall that electrostatics can be useful for electrostatic precipitators:

Answer 1

• remove the dust or soot in smoke

- used in chimneys

Question 2

Recall that electrostatics can be useful for spraying:

Answer 2

• spray painting

- crop spraying

Question 3

How defibrillators are used by medical staff in emergencies

Answer 3

• two paddles are charged and are put in good electrical contact with the patient’s chest
• the defibrillator discharges into the patient
• charge is then passed through the patient to make the heart contract
• care taken not to shock operator

Question 4

What is a defibrillator

Answer 4

Restarts the heart when it has stopped

Question 5

How do defibrillators work?

Answer 5

By discharging charge

Question 6

How do electrostatic precipitators work

Answer 6

• metal plates and grids are installed in the chimney and are connected to a high voltage. Dust passes through the grid and is charged.
• the dust particles are attracted to earthed plates, where they form larger particles. Large particles fall back down the chimney when they are heavy enough or when the plate is struck

Question 7

Explain how static electricity can be useful for electrostatic dust precipitators to remove smoke particles etc from chimneys

Answer 7

• dust passes through charged metal grid or past charged rods
• dust particles become charged
• plates are earthed or charged opposite to grid
• dust particles attracted to plates
• plates struck and dust falls to collector

Question 8

Explain how static electricity can be useful for paint spraying

Answer 8

• spray gun charged
• paint particles charged the same so repel giving a fine spray and coat
• object charged oppositely to paint so attracts paint into the ‘shadows’ of the object giving an even coat with less waste

Question 9

Explain how static electricity is used in electrostatic dust precipitators to remove smoke particles etc from chimneys

Answer 9

• high voltage metal grids put into chimneys to produce a charge on the dust
• dust particles gain or lose electrons
• dust particles induce a charge on the earthed metal plate
• dust particles are attracted to the plates

Question 10

Explain how static electricity is used in paint spraying, in terms of paint and car gaining and losing electrons and the resulting effects

Answer 10

• the negatively charged paint has gained electrons from the gun
• car panel is made positively charged by removing electrons from it to make it attract the paint
• the charging process causes the paint to form a fine spray so is applied evenly
• the result is a neutral, painted car panel and means that less paint is wasted and even the back and sides of the object that would be in the shadow receive a coat of paint