F2 — Science Electricity Exercise Top
Do not just check the answer; read the why.
A1. Answer: B Explanation: In a series circuit, there is only one path for electrons. The number of electrons passing point A per second equals the number passing point B. Current is constant.
A2. Answer: C (6V) Explanation: The "top rule" for parallel circuits: Voltage is the same across every branch. The battery pushes 6V, so every component gets the full 6V.
A3. Answer: B (Series) Explanation: An ammeter measures flow through a component. To measure how many electrons go through a bulb, you must break the wire and put the ammeter in the same path (series). Putting it in parallel creates a short circuit.
A4. Worked Solution:
A5. Answer: 1.8V Explanation: In series, voltages add up to the battery voltage. ( V_battery = V_L1 + V_L2 ) ( 3V = 1.2V + V_L2 ) ( V_L2 = 1.8V )
A6. Check your drawing against these rules: f2 science electricity exercise top
A7. Answer: 3 Amperes (A) Explanation: Branch 1: V=9V, R=3Ω. I = 9/3 = 3A.
A8. Answer: 1.5 A Explanation: Branch 2: V=9V, R=6Ω. I = 9/6 = 1.5A.
A9. Answer: 4.5 A Explanation: Total current = Sum of branch currents. ( I_total = 3A + 1.5A = 4.5A ).
A10. Answer: They stay the same brightness. Explanation: This is the top trick question in F2 science.
1. Which of the following correctly states Ohm's Law? A. Current is directly proportional to Voltage. B. Voltage is inversely proportional to Resistance. C. Resistance is directly proportional to Current. D. Current is inversely proportional to Voltage.
2. In a Series circuit, if one bulb burns out: A. The other bulbs will shine brighter. B. The other bulbs will stay lit. C. The circuit is broken and all other bulbs go out. D. The battery will explode. Do not just check the answer; read the why
3. Which component is used to measure the potential difference across a resistor? A. Ammeter B. Voltmeter C. Ohmmeter D. Galvanometer
4. Which wire connects the metal casing of an appliance to the ground to prevent electric shock? A. Live wire B. Neutral wire C. Earth wire D. Fuse wire
Use Ohm’s Law (V = I × R) to solve.
Refer to the described circuit: Two bulbs (L1, L2) in series with a 3V cell. An ammeter reads 0.5A.
Q4. What is the total resistance of the circuit? (Use ( V = IR ))
Q5. If a voltmeter is placed across L1 and reads 1.2V, what is the voltage across L2? Before you tackle the exercises
Q6. Draw the circuit diagram for the description above. (Answer key: Draw a rectangle. Cell on the left, ammeter on top, L1 on right, L2 on bottom, all in one closed loop).
One of the most common exam questions asks you to differentiate between Series and Parallel circuits. Here is a cheat sheet for your exercise book:
| Feature | Series Circuit 🔗 | Parallel Circuit 🔀 | | :--- | :--- | :--- | | Path | Only one path for the current to flow. | More than one path for the current to flow. | | If one bulb blows? | The circuit breaks; all other bulbs go off. | The other bulbs stay lit. | | Current (I) | Same throughout ($I_total = I_1 = I_2$). | Splits up ($I_total = I_1 + I_2$). | | Voltage (V) | Splits up ($V_total = V_1 + V_2$). | Same across each branch ($V_total = V_1 = V_2$). | | Resistance (R) | Increases (Adds up). | Decreases (More paths = easier flow). |
Real World Example: Why do we wire our homes using Parallel circuits? Because if the TV turns off, we don't want the refrigerator and lights to turn off too!
Before you tackle the exercises, make sure you understand these three pillars of Form 2 Electricity.