Define each, with units: (a) electric current; (b) potential difference (voltage); (c) resistance. State Ohm's law.
2. [3 marks]
A \(60\) Ω resistor is connected to a \(120\) V source. (a) Calculate the current. (b) Calculate the power dissipated using two different formulas to verify.
3. [3 marks]
Three resistors of \(2\) Ω, \(3\) Ω, and \(6\) Ω are connected in parallel across a \(12\) V battery. Calculate (a) the total resistance; (b) the total current.
4. [3 marks]
MC: An ammeter must always be connected:
5. [3 marks]
State the right-hand rule for a current-carrying wire. Sketch the magnetic field lines around (a) a long straight wire with conventional current flowing upward; (b) a circular current loop.
[Field-line sketches]
Part B — Thinking & Investigation [15 marks]
6. [5 marks]
A \(24\) V battery is connected to a \(4.0\) Ω resistor in series with a parallel combination of \(6.0\) Ω and \(3.0\) Ω. Find: (a) total resistance; (b) total current; (c) voltage across each part of the circuit; (d) current through each parallel branch; (e) power dissipated by each resistor (verify total = \( V_T I_T \)).
7. [5 marks]
Investigation design: Design an experiment to verify Ohm's law for a fixed resistor. Identify IV/DV/CV, equipment, the data table, the graph you would plot (and what its slope tells you), and one source of error and how to reduce it. State what shape of \(V\)–\(I\) graph would indicate a non-ohmic component.
8. [5 marks]
A motor takes \(8.0\) A from a \(120\) V mains supply. Of the input, \(85\%\) is converted to mechanical work, the rest is dissipated as heat. (a) Calculate input power. (b) Calculate useful mechanical output power. (c) Heat dissipated per second. (d) If running 5 hours, how much electrical energy (in kWh and J) is consumed?
Part C — Communication [15 marks]
9. [5 marks]
Draw a clear schematic for a circuit with: a 12 V battery, a switch, a 6 Ω resistor in series with a parallel combination of two lamps (12 Ω each), and a voltmeter measuring the voltage across the parallel section, and an ammeter measuring total current. Label every component.
[Schematic]
10. [5 marks]
In a paragraph (5–7 sentences), explain how a simple DC motor works. Use the terms: armature, commutator, brushes, magnetic field, current, force on a current-carrying wire, right-hand rule.
11. [5 marks]
Compare and contrast (table OR paragraph): series vs. parallel circuits. Include: total resistance, current behaviour, voltage behaviour, what happens if one component fails, real-world example of each.
Part D — Application [15 marks]
12. [5 marks]
STSE — Household electricity bill: A house uses (per day, on average): refrigerator \(150\) W for 24 h; clothes dryer \(5000\) W for \(0.5\) h; lighting \(200\) W for 6 h; TV \(120\) W for 4 h. (a) Calculate daily energy consumption (kWh). (b) Monthly cost at \(\$0.13\)/kWh (30 days). (c) Suggest two specific changes that would reduce monthly cost and estimate savings.
13. [5 marks]
A typical Canadian house has 15 A circuit breakers on most outlet circuits at \(120\) V. (a) Calculate the maximum power that one circuit can deliver. (b) A space heater is rated \(1500\) W and a hair dryer \(1200\) W. Can both run simultaneously on the same circuit? Show calculations. (c) Why is it dangerous to "string" multiple power bars to bypass a tripped breaker?
14. [5 marks]
A coil with \(N=200\) turns is wrapped around an iron core to form an electromagnet. Current of \(2.5\) A flows. (a) Describe (qualitatively, with a sketch) the magnetic field inside and outside the coil. (b) State two factors that increase the strength of the field. (c) Name three common technologies that rely on electromagnets and explain how each uses one in operation.