# Physics P4

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What causes static charge to build up?
Build up of static is caused by friction
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What particles move when static charge is built up?
Electrons
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How can static electricity be a nuisance?
1) It attracts dust 2)Clothing clings and crackles 3)Shocks from door handles
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How can static electricity be dangerous?
1)A lot of charge can build up on clothes and cause a spark 2)When filling up fuel, using grain chutes and paper rollers, static can build up and cause a spark
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How can you reduce the danger of getting a static electric shock?
Earthing: This is where a charged object is connected to the ground using a conductor and provides an easy route for the static to travel to the ground. Insulating mats can prevent static electricity from moving through them.
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Give three examples of how static electricity might be useful
Paint sprayers(Getting and even coat) Dust precipitators(cleaning up emissions) Defibrillators(Restarting a heart)
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Explain how static electricity is used in paint sprayers
The spray gun is charged, which charges up the small drops of paint. The paint drops repel each other as they have the same charge, so you get a very fine spray. The painted object is given an opposite charge to the gun.This attracts the paint.
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What happens to the current when you increase the voltage?
More current will flow
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Why is earthing and double insulating useful in a plug?
The reduce the danger of an electric shock
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Does increasing the thickness of a wire increase the resistance?
No, the thinner the wire, the more resistance it has
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What is amplitude?
Amplitude tells you how much energy the wave is carrying, or how load the sound is.
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What is the frequency of a wave?
How many complete waves there are per second. Frequency is measured in Hertz
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What are the advantages of Ultrasound over X-rays?
1)Ultrasound is safer than X-rays 2)Ultrasound can detect soft tissue whereas X-rays cannot
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What can Ultrasound be used for?
1) Breaking down accumulations in the body-getting rid of kidney stones 2)For body scanning(eg when the foetus is in the womb))
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What is the definition of Half-Life?
Half Life is the time taken for half of the radioactive nuclei to decay
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Why is Beta and Gamma radiation more dangerous outside the body than Alpha radiation is?
Because Beta and Gamma can penetrate the skin and get inside your organs whereas Alpha cannot penetrate the skin.
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How are gamma rays used to treat cancer?
The gamma rays are focused on the tumor using a wide beam. This beam is rotated round the patient with a tumour at the centre. This minimises the exposure of normal cells to radiation, and so reduces the chances of damaging the rest of the body.
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How is Alpha radiation used in Smoke alarm?
A weak alpha source is placed near two electrodes. The source causes ionisation of the air particles which allows current to flow. If there is a fire, smoke particles cause less ionisation to occur which causes the alarm to sound.
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Explain how a chain reaction is created in a nuclear reactor
Uranium atoms split up and release energy in the form of heat-this is nuclear fission.The heat is the used to heat water to produce steam.The steam turns a turbine, which drives a generator that produces electricity
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What is the difference between nuclear fission and nuclear fusion?
Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy
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Why is cold fusion accepted as a realistic method of energy production?
Few scientists were able to reproduce the results reliably so it hasnt been accepted as a realistic method of energy production
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## Other cards in this set

### Card 2

#### Front

What particles move when static charge is built up?

Electrons

### Card 3

#### Front

How can static electricity be a nuisance?

### Card 4

#### Front

How can static electricity be dangerous?

### Card 5

#### Front

How can you reduce the danger of getting a static electric shock?