Electricity Flashcards
What is the value of mains voltage (in the UK)?
Mains voltage is 230V.
Describe what would happen to a positive charge if it was placed in the field shown.
A positive charge would accelerate towards the negative plate.
What is the name of this component?
Loudspeaker
What is the name of this component?
npn transistor
How could the air-conditioning circuit (shown) be changed so that it switches on at a different temperature?
To switch the circuit on at a different temperature, the variable resistor could be adjusted.
Which quantity is represented by the symbol Q?
Q = charge
What is the name of this component?
Motor
What is the name of this component?
L.E.D. (light-emitting diode)
What is the name of this component?
Capacitor
What unit is energy measured in?
Energy is measured in joules (J).
Round off this number to 3 significant figures.
1,526.33
1,526.33 rounded off to 3 significant figures is
1,530
(the ‘2’ has been rounded up to 3)
How many pencils are there?
What unit is voltage measured in?
Voltage is measured in volts (V).
What does the prefix k stand for?
k stands for kilo
kilo = x 103
What unit is charge measured in?
Charge is measured in coulombs (C).
What effect does an electric field have on a charge?
An electric field causes a charge to accelerate (due to applying an unbalanced force)
What is the definition of the term power?
Power is defined as the amount of energy used per second.
What is the definition of current?
Current is how much electrical charge flows (past a point) in one second.
What unit is power measured in?
Power is measured in watts (W).
Which quantity is represented by the symbol P, in the equation shown?
P = power
Describe how to use an ammeter to measure the current in a component.
An ammeter must be connected in series with a component.
Which quantity is represented by the symbol R?
R = resistance
Round off this number to 3 significant figures.
6.22789
6.22789 rounded off to 3 significant figures is
6.23
How could the resistance of a component be found from this graph?
The resistance could be found by
(a) calculating the gradient of the graph
(b) choosing a point on the graph and calculating voltage / current
What is the name of this component?
Fuse
What does d.c. stand for and what does it mean?
d.c. stands for direct current, which means the electrons flow in one direction only (negative to positive).
What is the name of this component?
Variable resistor
What is the name of this component?
Resistor
What is the name of this component?
Lamp
Round off this number to 3 significant figures.
3.14159
3.14159 rounded off to 3 significant figures is
3.14
What does a.c. stand for, and what does it mean?
a.c. stands for alternating current, which means the electrons change direction every fraction of a second.
How could the air-conditioning circuit (shown) be changed so that it performs the opposite job?
The circuit can be changed to perform the opposite job by swapping the thermistor with the variable resistor.
What does the prefix G stand for?
G stands for giga
giga = x 109
Will the L.E.D. in this circuit switch on?
Explain your answer.
No - the L.E.D. will not switch on.
The positive terminal of the L.E.D. is not connected to the positive terminal of the battery.
Which quantity is represented by the symbol V, in the equation shown ?
voltage
(or potential difference)
Round off this number to 3 significant figures.
0.0025668
0.0025668 rounded off to 3 significant figures is
0.00257
What does the prefix m stand for?
m stands for milli
milli = x 10-3
What is the name of this component?
MOSFET (transistor)
What is the name of this component?
Diode
What is the name of this component?
L.D.R. (light-dependent resistor)
Which quantity is represented by the symbol I?
I = current
What does the prefix M stand for?
M stands for mega
mega = x 106
What unit is time measured in?
Time is measured in seconds (s).
Describe how to use a voltmeter to measure the voltage across a component.
A voltmeter must be connected in parallel with a component.
What does the prefix µ stand for?
µ stands for micro
micro = x 10-6
Why does an L.E.D. always have a resistor connected in series with it?
An L.E.D. always has a resistor connected in series with it to protect the L.E.D.
The resistor will limit the current in the L.E.D.
Which quantity is represented by the symbol t?
t = time
A hairdryer has an operating current of 6.5 amperes.
What value of fuse should be used in the plug of the hairdryer?
The fuse rating has to be higher than the operating current.
If the current is 6.5A, a 13A fuse should be used.
What unit is current measured in?
Current is measured in amperes (A).
In the diagram shown, what type of charge does the particle have?
Explain your answer.
The particle has a negative charge.
The particle is negative because it is attracted to the positive plate.
Describe what would happen to a negative charge if it was placed in the field shown.
A negative charge would accelerate towards the positive plate.
What does the prefix n stand for?
n stands for nano
nano = x 10-9
What unit is resistance measured in?
Resistance is measured in ohms.
What is the name of this component?
Cell
What is the name of this component?
Battery
The voltage of a supply is a measure of the ………………. given to the charges in a circuit.
The voltage of a supply is a measure of the ENERGY given to the charges in a circuit.
Will the L.E.D. in this circuit switch on?
Explain your answer.
Yes - the L.E.D. will switch on.
The positive terminal of the L.E.D. is connected to the positive terminal of the battery.
What is the purpose of a transistor?
A transistor acts as an electronic switch.
(it switches on above a certain voltage)
How many types of electric charge are there, and what are their names?
There are two types of electric charge - positive and negative
