# AS key facts

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• Created by: dan
• Created on: 03-03-14 21:37
What is a Scalar quantity?
One that has a Magnatude but no direction
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What is a Vector quantity?
Once that has magnitude and direction
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What is Acceleration?
Rate of change of verlocity
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What is a Newton?
It is a force that causes a mass of one kilogram to have an acceleration of one metre per second every second
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What is a couple?
It is a pair of equal and parallel but opposite, which tend to produce a rotation only
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What is a moment?
It is the force multiplied by the perpendicular distance
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What is Density?
Mass per unit volume
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What is pressure?
Force per unit area
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What is what is one Joule?
the work done when a force of one newton moves its point of application one metre
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What is a watt?
One joule per second
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What is stress?
The force per unit cross-section
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What is strain?
Extension per unit length
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What is Charge?
Current x Time
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What is a coulomb?
total charge supplied by a current of one amp in one second
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What is Kirchhoff's first law?
The sum of the current entering any junction is always equal to the currant leaving a junction.
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What is Electromotive force (E.M.F)?
the energy transferred per unit charge when one other type of energy is converted into electrical energy
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What is potential differance?
the electrical energy transferred per unit charge when electrical energy is converted into another form of energy
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What is Ohm's law?
the current through a conductor is proportional to the potential difference across it provided conditions remain constant
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How to find the resistivity of a wire
Resistance x cross-sectional area / length of wire
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what is a kilowatt-houre (kWh)?
it is 1000 watts for 3600 seconds so therefore 3600000J
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What is a node?
it is a point in a stationary wave at which there is no displacement of the particals at any time
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What is an antinode?
the displacement of the particles in a stationary wave varies by the maximum amount
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What is an electronvolt?
it is the energy an electron, with charge -1.6x10^-19C, acquires when it rises through a potential differance of one volt
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What is the threshold frequency?
it is the lowest frequency of radiation that will result in the emission of electrons from a particular metal surface
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## Other cards in this set

### Card 2

#### Front

What is a Vector quantity?

#### Back

Once that has magnitude and direction

### Card 3

#### Front

What is Acceleration?

### Card 4

#### Front

What is a Newton?

### Card 5

#### Front

What is a couple?