Current-Voltage Graphs for Components · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Reading current against voltage

Science · Energy · ages 14-15
Name ______________________   Date ____________

  1. A straight line IV graph through zero means the resistance stays constant.

    Circle one:   True   False

  2. Where does the ammeter go when you plot an IV graph?

    • In series with the component
    • Across the component
    • Across the supply

  3. Two resistors give straight IV lines. One line is steeper. What does that tell you?

    • It has higher resistance
    • It heats up more
    • It has lower resistance

  4. A graph stays near zero for negative voltages and climbs fast for positive ones. What is it?

    • A lamp with a cold filament
    • A resistor with a loose wire
    • A diode passing current one way only

  5. A component graph bends flat at higher voltages. Which component is it?

    • Fixed resistor
    • Filament lamp
    • Fuse wire

  6. You reverse the supply on a diode circuit. What happens to the current?

    • It doubles in the same direction
    • It stays near zero on the reverse side
    • It follows a straight line

  7. You flip the supply and one graph keeps a flat side while the others mirror through zero. Which component gives the flat-sided graph?

    • The resistor
    • The lamp
    • The diode

  8. A learner says the lamp graph bends because the meters are broken. What is the real cause?

    • The meters add resistance to the circuit
    • The filament heats up and its resistance climbs
    • The supply voltage drops to zero
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Reading current against voltage W1-mt_n_CiOa-05J-s1

  1. True · Steady proportion between current and voltage means steady resistance.
  2. In series with the component · The ammeter must carry the current, so it sits in series.
  3. It has lower resistance · Steeper means more current for each volt, which is lower resistance.
  4. A diode passing current one way only · One flat side plus one climbing side is the diode signature.
  5. Filament lamp · Only the lamp heats up and gains resistance as current flows.
  6. It stays near zero on the reverse side · Reverse is the blocked side, so almost nothing flows.
  7. The diode · Only the diode refuses to mirror, staying flat on reverse.
  8. The filament heats up and its resistance climbs · Heating, not broken meters, raises the resistance and flattens the graph.
Worksheet · LightMySky