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Pass the CHP exam.Understand the physics.
The CHP exam is not a memorization test. It tests whether you think like a health physicist. Half-Life Academy teaches the underlying models — so you can derive answers you've never seen before.
No account needed for the first lesson.
M03 · Lesson 2
Inverse square law
Exposure rate decreases with the square of distance from a point source. Move twice as far — rate drops by a factor of four.
Ẋ₂ / Ẋ₁ = (r₁ / r₂)²~0
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Part II teaching problems
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LLM-graded simulations
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Why Half-Life Academy
Most candidates fail because they prepared for the wrong exam.
The CHP exam is an applied physics reasoning test. Examiners expect you to connect dose-response models, shielding calculations, and detector theory — not recite regulation numbers from memory.
Half-Life Academy organizes study around the physical models behind each domain: inverse square and buildup before shielding tables, interaction cross sections before dosimetry calculations, detector statistics before efficiency corrections.
Learn. Practice. Master. — each mode builds on the last, from conceptual models to retrieval under exam conditions.
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Lessons that build models, not slide decks.
Every lesson opens with the physical model before regulations or procedures — with interactive parameters where the math matters.
Lesson 2 of 7 · ~18 min
Inverse square law
For a point source, exposure rate decreases with the square of distance. At 1.0 m, the rate is 12.5 mR/hr. Adjust distance to see the predicted rate.
Ẋ₂ / Ẋ₁ = (r₁ / r₂)²Predicted exposure rate: 2.0 mR/hr
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This is what a Half-Life Academy question feels like.
Not recall. Applied physics. One representative question from the Radiation Shielding module.
Radiation shielding · Difficulty 3/5
A point source of ¹³⁷Cs produces an exposure rate of 12.5 mR/hr at 1.0 m. Ignoring buildup, at what distance will the exposure rate decrease to 2.0 mR/hr?
Illustrative sample. No signup required for the first lesson.