# G482 - module 1

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Define current
net flow of charged particles
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describe the difference between current flow in a metal and an electrolyte
in a metal, the current is due to movement of electrons, whereas in an electrolyte, the current is due to movement of ions.
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what is the difference between conventional current and electron flow?
electrons flow from the negative terminal in a circuit to the positive terminal, whereas conventional current goes from +ve to -ve.
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what is the equation for charge involving current and time?
delta Q = I delta t ===> the change in charge is equal to the change in time multiplied by the current flowing through it
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define the coulomb
unit of charge, the quantity of electricity conveyed in one second by a current of one ampere, 1C = 1A x 1s
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how can an ammeter be used to measure the current in a circuit?
connect the ammeter in series with the components of the circuit
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what is the charge on an electron?
e = -1.6 x 10^-19 C
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what is Kirchhoff's first law?
Kirchhoff’s First Law states that the total current entering a junction is equal to the total current leaving the junction. OR The algebraic sum of currents at a junction is zero.
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how is Kirchhoff's first law an example of conservation or current?
Whatever current enters a given junction in a circuit must leave that junction since charge cannot be created or destroyed at a junction. Charge cannot escape from the wire but has to flow around the circuit.
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define mean drift velocity
The actual velocity of an electron between collisions is of the order of magnitude 106 m s–1, but its haphazard journey causes it to have a drift velocity towards the positive end of the battery. Since there are billions of them we use the term v.
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give an equation using mean drift velocity to calculate the current
I=Anev , I=current, A=Cross-sectional area, n=number density, e=elementary charge, v=mean drift velocity
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descirbe the difference between conductors, semiconductors and insulators in terms of number density n.
conductors have the most free electrons available for conduction, insulators have very few as they have full electron shells, semiconductors are somewhere in the middle.
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## Other cards in this set

### Card 2

#### Front

describe the difference between current flow in a metal and an electrolyte

#### Back

in a metal, the current is due to movement of electrons, whereas in an electrolyte, the current is due to movement of ions.

### Card 3

#### Front

what is the difference between conventional current and electron flow?

#### Back ### Card 4

#### Front

what is the equation for charge involving current and time?

#### Back ### Card 5

#### Front

define the coulomb

#### Back 