Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

physics specific vocabulary > electricity > Flashcards

electricity Flashcards

(70 cards)

Start Studying
1
Q

reason why increasing resistance may not affect voltage

A

voltmeter may not be sensitive enough

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

steel increases

A

mechanical strength cables

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

why superconducting wire increase efficiency

A

no resistance no power loss

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

state and explain what happens to brightness of lamp if connected to power supply w/ internal resistance(2)

A
  • lamp less bright

- power now wasted

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

application superconductor and why (2)

A

MRI / strong magnetic field

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

application superconductor and why (2)

A

MRI / strong magnetic field

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

application superconductor and why (2)

A

transformer - no energy dissipation

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

what’s a superconductor and how does it become a superconductor (3)

A

superconductivity means a material has zero resistivity/resistance (1)
resistivity decreases with temperature or idea of cooling (1)
becomes superconducting when you reach the critical/certain/
transition temperature (1)

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

what happens to resistance of cable when embedded filaments are made superconducting (3)

A 
the resistance decreases (to zero) (1)
copper still has resistance (1)
but this is in parallel with filaments (which have zero resistance) (1)
hence total resistance is zero (1)
current goes through filaments (1)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

explain why resistance NTC decreases as temp rises (2)

A
  • increased temp = release electrons

- current increases as charge carrier density increases

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

2 heating element at 230V 500W connected to 230V supply in series + parallel
explain why only one will give power output 1KW(6)

A

parallell

  • lower resistance = higher current = more power
  • parallel voltage across each constant whereas in series split between the 2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

in potential divider questions ALWAYS

A

give p.d. affect on all resistors / components

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

to say __ of parallel branch say

A

resistance in parallel combination decreases

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

what give largest resistance

A

series

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

define emf

A

emf is the work done / energy transferred by a voltage source / battery / cell ✓per unit charge✓

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

explain why voltage on graph always less than emf - why difference voltage emf becomes larger w/ increasing current

A

-internal resistance
-terminal pd = emf - lost volts
-lost volts increase as current increases
-

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

if gives 2 requirements for something to work and asks if it works

A

state both

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

why voltmeter has a high resistance

A

so current is 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

remember 2 cells =

A

double emf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

1 reason for rechargeable battery to have low internal resistance

A

charges quicker as less energy wasted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

define emf

A

joules per coulomb (of charge)/work done per unit charge

where charge moved (whole way) round circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

lost volts

A

emf - terminal pd

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

2 points for why voltage measured less than emf

A
  • work done in battery due to internal resistance

- lost volts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

why would ammeter reading be greater if motor in series is lifting a load

A

battery has to provide more energy / power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
why something will not start with higher internal resistance e
terminal pd will not be high enough
26
when talking about effect of switch always say
when switch closed CURRENT FLOWS then rest
27
asks how values obtained from internal resistance practical
by altering variable resistor
28
what two statements to say when voltmeter < emf
- current through battery - pd lost across internal resistance - work done to lose pd
29
why does pd between two points in circuit not change even if cell replaced w/ cell of internal resistance (2)
- terminal pd decreases | - BUT ratio of resistors remain constant OR voltmeter not sensitive enough to measure change
30
potential divider equation
combination resistors in series connected to voltage source
31
3 points to make in potential divider 3 marker about pd across each component (3)
- change in resistance one = pd change - pd across component + pd other = supply pd (in series) - so change in pd on other component
32
never give fractional ! always
decimals
33
2 marker potential divider question
- resistance (__) decrease = pd decrease | - so greater (PROPORTION/SHARE) PD to (_)
34
2 marker on why pd wouldn't change if resistance of different parallel branch changed
``` no change (1) constant pd across parallel branches (1) ```
35
define 1 volt
1 joule per couloumb charge
36
advantage to high value resistance in potential divider circuit
reduced current
37
compare potential divider in controlling current across resistor to variable resistor circuit (2)
- potential divider = sensitive control current | - variable resistor = larger current but not near 0A
38
why resistance NTC decreases w/ temp increases (3)
- more charge carriers available - internal energy used to liberate electrons - more significant than vibrations lattice ions
39
for power and resistance equation
V squared / R
40
why does resistance of thermistor decrease as temperature rises (3)
-extra charge carriers released as temperature rises -increased thermal agitation of atoms resists flow of charge carriers - 1st effect overwhelms 2nd
41
brightness of lamps w/ same current
same
42
advantage and disadvantage to potential divider method of Current (2)
- adv- better control 0- to max | - disadvan-power wasted lower half resistor always carries
43
adv and disas to rehostat method
-adv- easier to connect | disad- minimum current through bulb never 0
44
temp measured at
voltmeter
45
3 points for how voltmeter reading across LDR changes as light increases - DIFFERENT AS ACROSS LDR
LDR resistance drops voltmeter reading decreases because more conduction electrons/charge carriers released
46
why resistance LDR decreases at higher temp (2)
- more charge carriers released - liberated electrons | - increases current
47
application superconductor and reason
- maglev trains / MRI - strong magnet | - no thermal energy produced
48
how to get readings for reverse bias
reverse cell
49
why non ohmic
resistance not constant
50
when asked how results obtained always say ( and in 6 markers)
variable resistor
51
for filament lamp 4 marker say
current heats filament | same in reverse direction / mirror image
52
practical use diode
protect against current surges
53
ohms law definition
VI directly proportional if temp constant
54
on emf graph questions - for value internal resistance
say modulus gradient is r
55
when pd across component is 0 say
no current flows
56
component placed in parallel between two components of equal pd =
0V as diff between two components NOT SAME
57
is bulb filament breaks
ignore from circuit
58
energy transformed across battery
from EMF
59
energy dissipate across battery
internal r
60
in describe filament IV curve for increasing temp say
increasing RATE of collisions
61
graph relationship power and current
P=I^2R therefore y=x^2 graph
62
on VI graph for resistance NEVER
find gradient tangent for point - only ever read off points
63
if voltmeter put in branch in series w/ resistor in parallel circuit current through that branch is
0A as voltmeter infinite resistance - therefore discard any resistance in that branch as no current flows through it
64
when a resistor in added in circuit - 2 marker explain as to why
increase resistance therefore limit max current therefore prevent cell from overheating ( current too high) = short circuit
65
if given gradient min and grad max how to find grad
mean
66
why would 2 cells in series go out faster than 2 cells in parallel
- 2 cells in parallel receive double the amount of energy per second - more charge per second passes through cells in series
67
what would happen If use battery with much higher internal resistance to start car
- wouldn't start | - lower terminal pd
68
if light intensity 450 W m-2 with 0.15 efficiency use
450 x 0.15
69
how to take measurements emf and V
Voltmeter connected across cell terminals ✓ Switch open, voltmeter records ε Switch closed, voltmeter records V
70
for potential divider never divide PD it's
SPLITTING OF PD

physics specific vocabulary (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions