Mini Physics
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Exit to Nuclear Physics

Radioactive Decay & Detector Lab

Switch between decay-law, counting, detector, and reaction modes to keep exponential trends, background subtraction, and measurement context aligned.

  • GCE A-Level H2 Physics 2027
Learning goals
  • Analyse random radioactive decay, activity, decay constant and half-life.
  • Apply conservation laws to nuclear equations and beta decay, including antineutrino evidence.

Interactive stageLive model

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Change one variable at a time and watch the model respond.

Lab setup

Main mode
12 h
6 cm
Data view and options
Options

Decay checkpoint

What to notice:

Prediction target:

      Practice run

      Choose a mode and checkpoint count when you want scoring.

      Run mode
      Try Nuclear Physics Quiz

      Choose your checkpoint count for guided or challenge mode.

      Study lensUse half-life, decay constant, activity, and exponential-decay relationships with the correct physical quantity and time unit.15 min activity

      Try this

      Name the quantity first: activity, measured count rate, background, or net source count rate. Then do the subtraction or decay step.

      Learn to

      • Use half-life, decay constant, activity, and exponential-decay relationships with the correct physical quantity and time unit.
      • Separate measured count rate, background count rate, net source count rate, and source activity in detector questions.
      • Compare detector readings and classify nuclear reactions without reducing every change to distance alone.

      Exam transfer

      • Decay data
      • Detector measurements
      • Reaction classification

      Governing idea

      Corrected count rate = measured count rate − background count rate. For a compact source far from the detector, count rate is approximately proportional to 1/r².

      Model boundary

      Counts fluctuate statistically and the geometry, detector efficiency, dead time, and absorption are simplified. The inverse-square trend is only approximate near the source.

      Avoid this trap

      Background is part of every measurement and must be estimated and subtracted; one short count is not an exact activity reading.

      How to explore

      Work through decay law, background correction, detector readings, and nuclear reactions with realistic noisy count data.

      Predict the outcome, change one variable at a time, then interpret the result. Completion records participation only and does not award mastery.

      Does this count towards my progress?