P4 ELECTRICAL CIRCUITS Flashcards
What is the equation for charge flow?
charge flow (Q) = current (I) x time (t)
What is the equation for potential difference?
potential difference (V) = current (I) x resistance (R)
What happens to the current when resistance increases?
when resistance increases, current decreases
What is directly proportional to current? (through an ohmic conductor)
potential difference
What does a diode do?
only allows current to flow in one direction
What happens to a thermistor when temperature increases?
the resistance decreases
What happens to an LDR (light dependant resistor) when light intensity increases?
the resistance decreases
What are the characteristics of a series circuit?
-the current throughout the circuit looks the same
-the total potential difference of the power supply is shared
-the total resistance is the resistance of all the components combined
(RTOTAL=R1 + R2 + …..)
What are the characteristics of a parallel circuit?
-the potential difference across each component is the same
-the total current is the current of all the components added together
-the total resistance of two resistors is less than the resistance
of the smallest individual resistor
(RTOTAL=1/R1 + 1/R2 …..)
What happens when a polyethene rod is rubbed against a dry cloth?
the dry cloth transfers its electrons to the rod, making it positively charged, therefore the rod is negatively charged
What happens when a perspex rod is rubbed against a dry cloth?
the dry cloth gains electrons from the rod, therefore making the rod positively charged and the cloth negatively charged
What are two cells called?
a battery
