AS ELECTRICITY EXAM ACTUAL QUESTIONS AND ANSWERS
Current rule for a series circuit - CORRECT ANSWER✅✅Current is the same everywhere
Current rule for a parallel circuit - CORRECT ANSWER✅✅Current in each branch adds up to the current
from the battery
Potential difference rule for a series circuit - CORRECT ANSWER✅✅pd across each component adds up
to the total pd across all components
Potential difference rule for a parallel circuit - CORRECT ANSWER✅✅Voltage across each branch is the
same as the voltage from the battery
Electrical current - CORRECT ANSWER✅✅The rate of flow of electrons around a circuit
Rule for EMF and pd in a circuit - CORRECT ANSWER✅✅The sum of the emfs round any complete loop
of a circuit is equal to the sum of the potential drops around the loop
Resistors in series - CORRECT ANSWER✅✅Total resistance equals the sum of the resistors
RT = R1 + R2 ...
Resistors in parallel - CORRECT ANSWER✅✅1/RT=1/R1+1/R2...
Electrical power equation - CORRECT ANSWER✅✅P = IV
(I = current/A)
Resistance equation - CORRECT ANSWER✅✅R = V/I
(I = current/A)
Resistance - CORRECT ANSWER✅✅A measure of how hard it is for current to flow
, Measured in Ohms (Ω)
Resistance heating - CORRECT ANSWER✅✅Resistors get hot when electricity flows through:
P = IV and V = IR
P = I2R or P = V2/R
EMF (ε) definition - CORRECT ANSWER✅✅The electrical energy per unit charge produced by a source of
electricity
EMF (ε) equation - CORRECT ANSWER✅✅ε = IR + Ir
or
ε = V + Ir
r = internal resistance
R = resistance of circuit
How do you measure internal resistance? - CORRECT ANSWER✅✅•Measure values of I and V for an
electrical source
•Plot V against I
•Use V = ε - Ir
•Gradient = -r
•Intercept = ε
Internal resistance (r) - CORRECT ANSWER✅✅The resistance of a source of electricity.
e.g. resistance of a battery
Diode facts - CORRECT ANSWER✅✅• Needs 0.6V (or more) in forwards bias to conduct
• Does not conduct in reverse bias (backwards)
Potential divider - CORRECT ANSWER✅✅Two or more resistors in series and a source of voltage.
Current rule for a series circuit - CORRECT ANSWER✅✅Current is the same everywhere
Current rule for a parallel circuit - CORRECT ANSWER✅✅Current in each branch adds up to the current
from the battery
Potential difference rule for a series circuit - CORRECT ANSWER✅✅pd across each component adds up
to the total pd across all components
Potential difference rule for a parallel circuit - CORRECT ANSWER✅✅Voltage across each branch is the
same as the voltage from the battery
Electrical current - CORRECT ANSWER✅✅The rate of flow of electrons around a circuit
Rule for EMF and pd in a circuit - CORRECT ANSWER✅✅The sum of the emfs round any complete loop
of a circuit is equal to the sum of the potential drops around the loop
Resistors in series - CORRECT ANSWER✅✅Total resistance equals the sum of the resistors
RT = R1 + R2 ...
Resistors in parallel - CORRECT ANSWER✅✅1/RT=1/R1+1/R2...
Electrical power equation - CORRECT ANSWER✅✅P = IV
(I = current/A)
Resistance equation - CORRECT ANSWER✅✅R = V/I
(I = current/A)
Resistance - CORRECT ANSWER✅✅A measure of how hard it is for current to flow
, Measured in Ohms (Ω)
Resistance heating - CORRECT ANSWER✅✅Resistors get hot when electricity flows through:
P = IV and V = IR
P = I2R or P = V2/R
EMF (ε) definition - CORRECT ANSWER✅✅The electrical energy per unit charge produced by a source of
electricity
EMF (ε) equation - CORRECT ANSWER✅✅ε = IR + Ir
or
ε = V + Ir
r = internal resistance
R = resistance of circuit
How do you measure internal resistance? - CORRECT ANSWER✅✅•Measure values of I and V for an
electrical source
•Plot V against I
•Use V = ε - Ir
•Gradient = -r
•Intercept = ε
Internal resistance (r) - CORRECT ANSWER✅✅The resistance of a source of electricity.
e.g. resistance of a battery
Diode facts - CORRECT ANSWER✅✅• Needs 0.6V (or more) in forwards bias to conduct
• Does not conduct in reverse bias (backwards)
Potential divider - CORRECT ANSWER✅✅Two or more resistors in series and a source of voltage.
