Starter quiz
How many parallel branches does the circuit shown have?- none
- one
- two
- three ✓
- four
-
- A series circuit contains a battery and one lamp. A second, identical lamp is added, in parallel with the first lamp. Which of the following statements is correct?
- The current through the first lamp increases.
- The current through the first lamp decreases.
- The current through the first lamp stays the same. ✓
-
- A series circuit contains a battery and one lamp. A second, identical lamp is added, in parallel with the first lamp. Which of the following statements is correct?
- The current through the battery increases. ✓
- The current through the battery decreases.
- The current through the battery stays the same.
-
- A series circuit contains a battery and one lamp. A second, identical lamp is added, in parallel with the first lamp. Which of the following statements is correct?
- The total resistance of the circuit increases.
- The total resistance of the circuit decreases. ✓
- The total resistance of the circuit stays the same.
-
- What potential difference is needed to make a current of 2.0 A flow through a 10 Ω resistor?
- 0.20 V
- 5.0 V
- 12 V
- 20 V ✓
-
- A lamp in a circuit has a potential difference 1.5 V across it and a current 3.0 A flowing through it. What is the resistance of the lamp?
- 0.50 Ω ✓
- 1.5 Ω
- 2.0 Ω
- 4.5 Ω
-
Exit quiz
The diagram shows a circuit with parallel branches. Which of the following quantities must be the same for every branch?- current
- potential difference (p.d.) ✓
- resistance
-
What is the missing current in the parallel circuit shown?- 1.2 A
- 2.2 A ✓
- 3.7 A
- 4.6 A
- 6.1 A
-
In the circuit shown, the potential difference across the resistor is ______ V.- '8.8' ✓
What is the resistance of the resistor in the circuit shown?- 0.33 Ω
- 0.44 Ω
- 3.0 Ω ✓
- 3.5 Ω
- 4.0 Ω
-
In the circuit shown, the potential difference across the lamp is ______ V.- '6.0' ✓
In the circuit shown, the resistance of the lamp is ______ Ω?- '0.6' ✓
Worksheet
Loading worksheet ...
Presentation
Loading presentation ...
Video
Lesson Details
Key learning points
- Current can be calculated using the equation: current = p.d. ÷ resistance (I = V ÷ R).
- The rules of current and p.d. for a parallel circuit can be applied to find some missing values of current and p.d.
- The equation I = V ÷ R can be rearranged so that either p.d. or R is the subject of the equation.
- If any two values in the equation I = V ÷ R are known, the third can be calculated.
- If only one value in I = V ÷ R is shown for a component, circuit rules need to be applied to the rest of the circuit.
Common misconception
To solve circuit problems you need only to put numbers into equations.
Talk through circuits with pupils before analysing them in order to develop an intrinsic understanding of how circuits work; research shows this improves pupils’ problem solving ability for electric circuits.
Keywords
Current - the rate of flow of charge in a circuit
Branch - a separate series loop in a parallel circuit
Resistance - a property of materials that makes it harder for current to flow
Potential difference (p.d.) - a measure of how 'hard' an electric field can push charge
Parallel - a type of circuit in which there are two or more separate branches
+