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Science · Grades 8–12

Circuits: series and parallel reasoning

The simple questions assume ideal wires and components with the stated resistance.

Make a worksheet

Understand the idea

Use ideal models carefully

The simple questions assume ideal wires and components with the stated resistance.

Describe connections

Series components share a path; parallel branches connect across the same two nodes.

Examples and reasoning

Ideal resistors in series carry the same

current

current

Ideal parallel branches connected across the same nodes share the same

potential difference

potential difference

Check your understanding

  1. Two resistors of 4 Ω and 7 Ω are in series. Find the equivalent resistance in Ω.

  2. A 12 V potential difference is across a 6 Ω resistor. Find current in A.

  3. A resistor carries 3 A with 5 V across it. Find power in W.

  4. Adding a positive-resistance parallel branch to an existing positive resistance makes equivalent resistance

    1. negative
    2. always larger
    3. unchanged in all cases
    4. smaller

Answers and marking notes

Answers and marking notes
  1. 11

    4 + 7 = 11

  2. 2

    I = V/R = 12/6 = 2

  3. 15

    P = VI = 5 × 3 = 15

  4. smaller

    smaller

Further reading and review references

These are reference links, not copied exercises, institutional endorsement or proof of independent review.

Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.