Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Electricity > Flashcards

Electricity Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

coulomb

A

SI unit of charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

current

A

The rate of flow of charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

anode

A

positive electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cathode

A

negative electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

power

A

rate of work done

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

elementary charge

A

the magnitude of the charge of an electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe what is meant by mean drift velocity

A

the average displacement of electrons along a wire per second, electrons collide with lattice, so go in diff dirrections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ohm’s Law

A

voltage and current are directly proportional when the temperature is constant. V=IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

semiconductor examples

A

silicon and germanium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

semiconductors get hot because

A

electrons need to travel faster to get the same current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

I = Anev

A

current = area x number density x elementary charge x drift velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

cell symbol short side

A

negative terminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

thermionic emission

A

the thermally induced flow of charge carriers from a surface or over a potential-energy barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

eV = 1/2mv^2

A

elementary charge x p.d = kinetic energy = work done on charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ohm

A

unit of resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

resistivity

A

A material’s opposition to the flow of charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

p = RA/L

A

resistivity = resistance x area / length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Negative temperature coefficient

A

resistance of semiconductor decreases when temperature is increased

19
Q

Kirchoff’s Second Law

A

sum of e.m.f. is equal to sum of p.d.s in a closed loop

20
Q

potential difference

A

measure of energy transferred per unit charge between two points.

21
Q

conventional current

A

positive to negative. opposite to electron flow

22
Q

electron flow

A

negative to positive. opposite to conventional current.

23
Q

Kirchoff’s First Law

A

sum of currents entering junction is equal to sum of current out of junction

24
Q

quantised

A

charge on an object always multiple of e

25
Q

number density

A

number of free electrons per cubic metre

26
Q

cell symbol long side

A

positive terminal

27
Q

potential difference in relation to charges

A

work done by the charges, they lose energy through component

28
Q

electromotive force

A

work done on the charges, they gain energy through component

29
Q

Threshold voltage

A

The minimum potential difference at which a diode begins to conduct

30
Q

large current needed (car battery)

A

low internal resistance

31
Q

small current needed (school power supply)

A

high internal resistance

32
Q

what causes internal resistance?

A

wires and components in power supplies, chemicals in cells

33
Q

resistance

A

A measure of how difficult it is for current to flow.

34
Q

lost volts

A

The difference between a source’s emf and the terminal voltage.

35
Q

terminal potential difference

A

The potential difference across the terminals of a power source. It is
equal to the source’s emf minus any voltage drop over the source’s internal
resistance.

36
Q

number density of copper?

A

10^29

37
Q

What is the difference between rms speed and drift velocity of electrons?

A

r.m.s. speed is random motion
Drift velocity is the mean velocity (of the free electrons)

38
Q

What is conductivity?

A

1/resistivity

39
Q

What is band theory?

A

In semiconductors, increasing thermal energy gives electrons enough energy to move from valence band to conduction band

40
Q

Why would you connect a resistor in series with an LED?

A

Minimises current flow, ensuring it doesn’t overheat.

41
Q

In series, if bulb fails, what happens to pd?

A

Components’ pds can be ignored.

42
Q

If two resistors are connected in parallel, and one’s resistance is 0, what is the total resistance?

A

0

43
Q

What is special about an open circuit?

A

Resistance = 0

44
Q

What is special about a shorted circuit?

A

Resistance = 0

Physics (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions