GCSE Physics P4

Explain what is meant by Earthing and give an example of where it is used

Connecting a charged object to the ground using an earth wire to prevent build-up of static charge. E.g. fuel tankers use them to prevent sparks that may cause the fuel to explode

1 of 25

How do anti-static sprays work?

Provide a conducting layer on a charged object so charge cannot build up

2 of 25

How is static electricity used in paint sprayers?

Spray gun is charged giving paint drops the same charge. This means they repel each other, giving a fine spray. Object is given opposite charge to gun, attracting paint spray. This method gives an even coat, less waste and no paint shadows

3 of 25

How is static electricity used to remove dust particles with a precipitator?

Dust particles meet a wire grid with a high voltage and gain electrons becoming negatively charged. The dust particles induce a charge on the earthed metal plates and become attracted so they stick forming larger particles. Plates vibrate + dust fall

4 of 25

How is static electricity used in a defibrillator to restart a heart?

Two paddles of a defibrillator are placed firmly on the patient's chest to ensure good electrical contact. Electric charge is passed through the patient to make their heart contract

5 of 25

Explain the different wires in a plug and their roles

Live wire - brown, carries voltage. Neutral wire - blue, completes the circuit providing a return path for the current. Earth wire - green/yellow, for safety it is connected to the case of an appliance to prevent it becoming live

6 of 25

What is meant by the term double insulated?

An appliance that has a non-conductive casing (e.g. plastic) is double insulated. It does not require an earth wire as it cannot become live

7 of 25

What do fuses do?

Fuses prevent fires because if a fault develops + the live wire touches the metal case, a big current flows and breaks the fuse. This causes the wire inside to melt and break the circuit preventing further damage. It stops overheating of the flex

8 of 25

What is a compression?

A region where particles are close together / region of high pressure

9 of 25

What is a rarefaction?

A region where particles are further apart / region of low pressure

10 of 25

Describe the movement of vibrations in longitudinal and transverse waves

Longitudinal waves - vibrations are along the same direction as the wave is travelling. Transverse waves - the vibrations are at 90 degrees to the direction of travel of the wave

11 of 25

What is the range of frequencies beyond human hearing?

Humans cannot hear frequencies above 20 000 Hz

12 of 25

How is ultrasound used to treat kidney stones?

High-powered ultrasound beam causes vibrations in the stones, breaking them down into smaller particles which can be passed out of the body in urine

13 of 25

What are the advantages of ultrasound over x-rays?

Ultrasound can image soft tissues and does not damage living cells

14 of 25

What is an alpha particle?

A helium nucleus containing 2 protons and 2 neutrons

15 of 25

What is a beta particle?

A fast-moving electron with no mass and a charge of -1

16 of 25

What is Half-life?

The time taken for half of the radioactive nuclei now present to decay

17 of 25

How is gamma radiation used to treat cancer?

Gamma rays are focused on tumour using a wide beam, the beam is rotated round the patient with the tumour at the centre. This minimises exposure of normal cells to radiation, reducing chances of damaging the rest of the body

18 of 25

How can radiation be used as tracers in medicine?

Short half-life Gamma and Beta emitters can be used in the body as they can penetrate tissue and so can pass out of the body and be detected

19 of 25

How do you know if there is a leak or blockage in a pipe using radiation?

If radioactivity being detected on the outside reduces or stops

20 of 25

Which types of people may be exposed to more background radiation?

People in aeroplanes (exposed to more cosmic rays), people working in medicine (x-rays) or close to nuclear power stations

21 of 25

What are the two metals used to radioactively date rocks?

Uranium and lead

22 of 25

Explain the process of nuclear fission

A slow-moving neutron is fired at a uranium atom which becomes unstable and splits into two nuclei releasing energy. 2 or 3 extra neutrons are also produced which contribute to the chain reaction

23 of 25

Advantages and disadvantages of nuclear fusion

A: can release large amounts of heat energy and used to generate electricity D: Only works at extremely high temperatures and pressures, will be hard to safely control these conditions

24 of 25

Why is cold fusion not accepted as a theory?

Few scientists have replicated results, no data or evidence, cannot be proved

25 of 25

Get Revising

GCSE Physics P4

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Similar Physics resources:

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Related discussions on The Student Room

Similar Physics resources: