2024 Exam Questions and Answers
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kirchoff's 1st law - Answer>>currents entering = currents
leaving
kirchoff's 2nd law - Answer>>sum of emf =sum of pd in a closed
loop
IV graph is a curve - Answer>>doesn't follow ohms law, as it
isn't directly preportional
lost volts equation - Answer>>E=V+IR
difference in resistance between conductors and insulators -
Answer>>insulator: higher resistivity as it is harder (not
possible) for an electric current to pass through
kirchoff's second law linked to conservation -
Answer>>conservation of energy: all energy has to come from
somewhere as it cannot be created of destroyed
kirchoff's first law linked to conservation - Answer>>charge is
conserved, this is a law of conservation
newtons first law - Answer>>an object will continue going in a
straight line tag a constant velocity unless acted upon by a
resultant force
Find number of charge carriers per m of wire (area=A, charge
carrier density=n) - Answer>>A x n
, number charge carriers passing a point per second (area=A,
charge carrier density=n, at speed=v) - Answer>>v x A x n
charge passing along the wire per second (area=A, charge carrier
density=n, at speed=v, with charge=q) - Answer>>v x A x n x q
Vout= - Answer>>Vsupply x l/L
potentiometer - Answer>>potential divider that allows a variable
voltage from 0 to Vsupply.
potentiometer equation - Answer>>Rout/Rtotal = Vout/Vtotal
temperature dependant resistor - Answer>>Thermistor. An
electric component that indicates temperature by the value of its
resistance
nct - Answer>>resistance decreases as temperature rises
how does ntc work - Answer>>temp increase, causes increase
conduction electrons released, so higher current flow.
ptc - Answer>>resistance increases as temperature increases
how does ptc work - Answer>>as temp increases, lattice ions
vibrate more, so more electron collisions with lattice ions. (also
happens in ntc)
LDR - Answer>>resistance decreases as light intensity
increases. because energy is absorbed, releasing more
conduction electrons.
load resistance - Answer>>resistance of the external circuit