Sparks

Question 1

What does an atom consist of?

Answer 1

An atom consists of a small positively charged nucleus surrounded by an equal number of negatively charged electrons.

Question 2

The law of electric charge states that:

Answer 2

Like charges repel, unlike charges attract.

Question 3

All electrostatic effects are due:

Answer 3

to the movement of electrons.

Question 4

What is in a stable atom?

Answer 4

In a stable, neutral atom there are the same amounts of positive and negative charges.

Question 5

Rubbing polythene rod

Answer 5

When a polythene rod is rubbed with a duster, electricons are transferred from the duster to the polythene, making the polyethene rod negatively charged.

Question 6

Rubbing acetate rod

Answer 6

When a acetate rod is rubbed with a duster, electrons are transferred from the acetate to the duster, making the acetate rod positively charged.

Question 7

In general an object has:

Answer 7

• A negative charge due to an excess of electrons
• A positive charge due to a lack of electrons

Question 8

Ions

Answer 8

Atoms or molecules that have become charged are ions.

Question 9

Dangers of electrostatic shock

Answer 9

• When flammable gases or vapours are present, or there is a high concentration of oxygen, a spark from static electricity could ignite the gases of vapours and cause an explosion.
• If a person touches something at a high voltage, large amounts of electric charge may flow through their body to earth,
• Even small amounts of charge flowing through the body can be fatal.

Question 10

When is static electricity a nuisance?

Answer 10

• Dust and dirt particles are attracted to insulators, such as TV screens.
• Clothes made from synthetic fibres often ‘cling’ to eachother and to the body.

Question 11

Electric shocks can be avoided in the following ways:

Answer 11

• If an object that is likely to become charged is connected to the earth, any build-up of charge would immediately flow down the earth wire.
• In a factory where machinery is at risk of becoming charged, the operator stands on an insulating rubber mat so that charge cannot flow through them to earth.
• Shoes with insulating soles are worn by workers if there is a risk of charge building up so that charge cannot flow through them to eart.

Question 12

How are fuel tankers connected to an aircraft?

Answer 12

Fuel tankers are connected to an aircraft by a conducting cable during refuelling.

Question 13

Anti-static spray

Answer 13

Anti-static sprays, liquids and cloths made from conducting materials carry away electric charge. This prevents a build-up of charge.