2024 Exam Questions and Answers
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electric current - Answer>>the rate of flow of charged particles
voltage - Answer>>a measure of the amount of energy
component transfer per unit of charge passing through it
what is the difference between potential difference & emf? -
Answer>>- potential difference is the electrical energy per
coulomb converted to other forms
- emf is the energy per coulomb supplied to a circuit
resistance - Answer>>opposition to the flow of current within a
conductor
Ohm's law - Answer>>the current through a conductor is
directly proportional to the potential difference across is, providing
the temperature of the conductor remains constant
why is resistance affected by temperature? - Answer>>1. an
increase in temperature causes an increase in internal kinetic
energy, which means ions in the metallic lattice vibrate more
vigorously
2. so delocalised electrons will be more likely to collide with the
ions present in the metal, losing their energy as they travel
through, which causes an increase in resistance
Kirchoff's first law - Answer>>the sum of currents entering a
junction is equal to the sum of currents leaving the junction
distribution of current in series circuits - Answer>>I1 = I2 = I3
, distribution of current in parallel circuits - Answer>>I total = I1 +
I2 + I3
Kirchoff's second law - Answer>>the total emf around a series
circuit is equal to the sum of the potential differences across each
component
distribution of potential differences in a series circuit -
Answer>>V total = V1 + V2 + V3
the total emf of a circuit is equal to the sum of the individual
potential differences on each branch (taking into account the
direction of their positive and negative sides)
distribution of potential differences in a parallel circuit -
Answer>>V1 = V2 = V3
voltage is the same on each branch
distribution of resistance in series circuits - Answer>>R total =
R1 + R2 + R3
why is the distribution of resistance in series circuits like this? -
Answer>>- resistors in series will have a total potential
difference across them that is the sum of their individual potential
differences
- V total = V1 + V2 + V3
- resistors in series will have the same current
- I1 = I2 = I3
- V = IR so IR total = IR1 + IR2 + IR3 and I is the same for each
resistor so R total = R1 + R2 + R3
distribution of resistance in parallel circuits - Answer>>1 / R
total = 1 / R1 + 1 / R2 + 1 / R3