Unit 3: Electric Circuits
Physics 2 · Unit 3 · Paper 2

Electric Circuits unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 24 terms and is the same for everyone, so a teacher can assign “Unit 3, Paper 2” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 37 min 34 points0/17 attempted
1

Internal resistance and terminal voltage

2

Why ammeters must have low resistance

3

Brightness reasoning

4

Reading a circuit diagram

5

Measuring resistance experimentally

6

Capacitance

7

RC circuit charging

8

Effect of adding a parallel branch

9

Capacitor charging graph

10

Kirchhoff's loop rule

11

Parallel resistors

12

Energy stored in a capacitor

Short answer 1. Define or explain: Energy dissipated during capacitor charging

3 pts

Short answer 2. Define or explain: Kirchhoff sign conventions

3 pts

Short answer 3. Define or explain: Ohm's law

3 pts

Short answer 4. Define or explain: Series vs parallel capacitor voltage

3 pts

Free response

10 pts

An ideal 12 V battery is connected in series with R₁ = 4.0 Ω. That resistor feeds a parallel combination of R₂ = 6.0 Ω and R₃ = 3.0 Ω.

Calculate the equivalent resistance of the circuit and the current delivered by the battery.

Calculate the potential difference across the parallel combination and the current in each of R₂ and R₃.

Calculate the power dissipated in R₁ and verify that the total power dissipated equals the power delivered by the battery.

An initially uncharged 100 μF capacitor is now connected in parallel with R₃. Determine the current delivered by the battery immediately after the connection is made, and a long time later.

Calculate the final charge on the capacitor and the energy stored in it.