Brainscape's Knowledge GenomeTM

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


See full index

Physics A-Level > Electric Current > Flashcards

Electric Current Flashcards

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

What is current

A

Passage of charge particles

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

What is the conventional direction of current

A

From positive to negative

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

What is potential difference

A

Work done per unit charge

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

What is resistance

A

Voltage / Current

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

What is Ohm’s Law

A

Pd across a metallic conductor is proportional to the current through it

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

What is the unit for resistivity

A

Ohm metre

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

What is a superconductor

A

A wire made of material that has zero resistivity at and below a critical temperature

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

What are superconductor used for

A

Making high-power electromagnetic for very strong magnetic fields

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

What does a heater on a circuit look like

A

Four squares

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

What does an electric motor look like on a circuit

A

Circle with M in the middle, with line under it

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

Describe the I/V graph for a wire

A

y=x

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

Describe the I/V graph for a filament lamp

A

Slanted s

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

Describe the I/V graph for a diode

A

No current below 0 volts, then large peak after a few volts

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

When does resistance in a wire increase

A

When temperature increases, causing positive ions to vibrate more and stop charge carries from passing through

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

What are thermistors used for

A

Temperature sensors

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

How do thermistors work with increases temperature

A

Increased temp decreases resistance

17
Q

What is a potential divider

A

A combination of resistors in series connected across a voltage source to produce a required pd

18
Q

What is equation for energy dissipation per time

A

This is P = IV

19
Q

Define emf

A

Electrical energy produced over unit charge

20
Q

What is internal resistance

A

Resistance of materials within a battery

21
Q

What is the difference between emf and potential difference

A

Emf is energy converted from chemical to electrical.

Voltage is energy converted from electrical to other forms

22
Q

How to determine the emf and internal resistance of a battery

A

Measure V and I across a resistor, change R and repeat, draw graph of V vs I, emf is y-intercept and internal is negative gradient

23
Q

What is the equation involving emf

A

V = emf - Ir

24
Q

Why is measured voltage not equal to emf

A

Battery has internal resistance, current passes through this, work is done and volts are lost

Physics A-Level (19 decks)

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