Electricity
Definitions: Electricity
- One exam question, the mark-scheme answer, and the exact phrases that score (highlighted, then listed below in the same colour).
Exam question
Define electric current.
Model answer
Electric current is the rate of flow of charge.
Marking points
1 mark each- 1rate of flow of charge(1)
Exam question
Define the coulomb.
Model answer
One coulomb is the charge that passes when a current of 1 A flows for 1 s.
Marking points
1 mark each- 1charge that passes when a current of 1 A flows for 1 s(1)
Exam question
Define the potential difference between two points.
Model answer
The potential difference is the energy transferred from electrical to other forms per unit charge.
Marking points
1 mark each- 1energy transferred from electrical to other forms per unit charge(1)
Exam question
Define the electromotive force (e.m.f.) of a source.
Model answer
The e.m.f. is the energy transferred from other forms to electrical per unit charge.
Marking points
1 mark each- 1energy transferred from other forms to electrical(1)
- 2per unit charge(1)
Exam question
Define resistance.
Model answer
Resistance is potential difference / current.
Marking points
1 mark each- 1potential difference / current(1)
Exam question
Define the ohm.
Model answer
One ohm is one volt per ampere.
Marking points
1 mark each- 1one volt per ampere(1)
Exam question
State Ohm's law.
Model answer
The current is proportional to potential difference, at constant temperature.
Marking points
1 mark each- 1current is proportional to potential difference(1)
- 2at constant temperature(1)
Exam question
Define the resistivity of a material.
Model answer
Resistivity is the property of a material defined by (unit Ω m).
Marking points
1 mark each- 1property of a material defined by (1)