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
0
Q

Resistance units

A

Ohms

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

How are voltage current and resistance related

A 
Voltage = current x resistance 
V = I x R
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ohms law

A

The current that flows through a conductor is directly proportional to the potential difference across its ends, provided it’s temperature remains constant

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

Q

A

Charge

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

What equation relates voltage, charge and energy

A

Voltage = energy/charge

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

Current

A

Rate of flow of charge

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

Why are metals good conductors of electricity

A

They have delocalised electrons

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

Why are non metals insulators

A

They have no delocalised charge carriers

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

I

A

Current

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

Equation that relates charge current time

A 
Current = charge/time 
I = Q/t
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Voltage

A

Joules per coulomb

Energy per unit charge

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

Resistance

A

How difficult it is for a current to flow through a material

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

In dark conditions LDRs resistance is what, and why

A

High, because they contain few free electrons

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

What happens to the resistance in LDRs when light is shone on them

A

More electrons are freed and the resistance decreases

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

What is the resistance like in a thermistor at room temperature

A

Large, because the number of free electrons is small

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

What happens to the resistance when a thermistor is warmed

A

The resistance decreases as the number of free electrons increases

16
Q

LEDS

A

Light emitting diodes - diodes that glow when a current is flowing through them

17
Q

Current in a circuit flows from

A

The positive terminal to the negative terminal (the delocalised electrons move about in the opposite direction)

18
Q

1 coulomb contains how many electrons?

A

6.25 x 10^18

19
Q

If the voltage increases, the current

A

Increases

20
Q

Why is the graph of current against voltage for a filament lamp bit a straight line

A

The wire in a filament lamp gets hotter for larger currents
More kinetic energy, more particle collisions
This increases the resistance

21
Q

1 mC (milliCoulombs)

A

0.001 C

22
Q

What does a variable resistor do

A

Changes the current in a circuit by changing the resistance

23
Q

LDRs resistance in dark conditions

A

Contain few free electrons and so have a high resistance

24
Q

LDRS resistance when light is shone on them

A

More electrons are freed and resistance decreases

25
Q

Thermistors uses

A

In temperature-sensitive circuits and devices such as fire alarms and thermostats

26
Q

LDRS uses

A

In light-sensitive circuits and devices such as photographic equipment automatic lighting controls and burglar alarms

27
Q

Unit of charge

A

Coulomb

Physics (17 decks)

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