12 exam-style questions (50 marks) in three tiers. Try each one on paper first, then check the model answer and mark scheme.
Chapter 4 notes12 questions · 50 marks
Showing 12 of 12 questions
Recall and simple application
State the units of charge and of current.
Calculate the charge transferred when a current of 0.25 A flows for 80 s.
A resistor has 6.0 V across it and carries 0.25 A. Calculate its resistance.
Complete: resistance is proportional to the ______ of a wire and inversely proportional to its ______.
Structured, exam-style
A motor draws 1.5 A for 4.0 minutes from a 12 V supply. (a) Calculate the charge transferred. (b) Hence calculate the energy transferred, using the meaning of p.d.
A wire of resistance 12 Ω is (a) cut to half its length; (b) separately, stretched to twice its length. Calculate the new resistance in each case.
(a) Calculate the p.d. needed to drive 0.30 A through a 15 Ω resistor. (b) Calculate the current a 46 Ω heater draws from 230 V.
Wire P has resistance 20 Ω. Wire Q is the same material but twice as long and half the cross-sectional area. Calculate Q’s resistance, explaining each factor.
Data, evaluation and explanation
A 4.0 A current flows for 10 minutes. (a) Calculate the charge transferred. (b) The charges pass through a 12 V supply and then the circuit. Calculate the total energy transferred. (c) State the meaning of the 12 V figure.
Readings for a fixed resistor: (2.0 V, 0.40 A), (4.0 V, 0.80 A), (6.0 V, 1.2 A). (a) Show that the resistor’s resistance is constant. (b) State the relationship between I and V shown by the data. (c) Predict the current at 10 V.
A nichrome wire has resistance 10 Ω. Calculate the resistance of wires of the same material when (a) the length is doubled, (b) instead the diameter is doubled (length unchanged), (c) the length is doubled AND the diameter is doubled. Explain each.
(a) Distinguish between conventional current and electron flow in a metal wire. (b) Explain why both descriptions describe the same current. (c) A 0.50 A current flows for 2.0 minutes; calculate the charge transferred, and state the charge if the current doubled for the same time.
Next step
A 30-mark paper set out like a school paper, with a separate mark scheme. Give yourself 40 min.
Question paper
30 marks · 40 min · 5 pages
5 multiple-choice questions and structured questions with answer lines. Chapter 4 (positive/negative charge in coulombs; current as rate of flow, conventional vs electron flow; Q = It; e.m.f. and p.d. in volts, p.d. as work per unit charge; R = V/I; resistance proportional to length and inversely to cross-sectional area).
Mark scheme
PROAnswers · Marking points · 3 pages
Model answers with a mark for each creditworthy point — for marking at home or in class.