Unit 7: Modern Physics
Physics 2 · Unit 7 · Paper 1

Modern Physics 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 21 terms and is the same for everyone, so a teacher can assign “Unit 7, Paper 1” 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

Fission vs fusion

2

de Broglie wavelength

3

Energy level diagrams

4

Electron diffraction

5

Alpha, beta and gamma decay

6

Radioactive decay is random

7

Photoelectric effect

8

Half-life

9

Photon energy

10

Work function

11

Conservation in nuclear reactions

12

Why intensity does not eject electrons below threshold

Short answer 1. Define or explain: Mass-energy equivalence

3 pts

Short answer 2. Define or explain: Wave-particle duality

3 pts

Short answer 3. Define or explain: Binding energy per nucleon

3 pts

Short answer 4. Define or explain: Compton scattering

3 pts

Free response

10 pts

This course has no free-response prompt tagged to this unit, so one from elsewhere in the course is used. It is still worth writing — the skill transfers.

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.