Uncertainties in measurements arise from the equipment used and the method employed. As the final paper for this year’s A-level Physics examination is imminent, and tests knowledge of uncertainties, it is worth taking a moment to examine the causes of uncertainty in more detail. We will do this by thinking about two example measurements; one … Continue reading Instrument resolution and experimental accuracy
Know your calculator!
When answering examination questions, it is important that your excellent knowledge of physics isn’t undermined by your calculator behaving in an unexpected way. You MUST be able to trust the answer given. But the situation is potentially complicated, not only because calculators don’t all behave the same way but also because they may not even … Continue reading Know your calculator!
Radiation detectors
The first device that comes to mind as a radiation detector (for use in schools) is probably the Geiger-Mueller (GM) tube. Although GM tubes can be used to detect all three types of ionising nuclear radiation (alpha, beta and gamma) they are subject to some important limitations. These shortcomings will be discussed below, together with … Continue reading Radiation detectors
Does radiation make things radioactive?
The short answer is “no” but the devil is always in the detail. Firstly, “radiation” here applies specifically to ionising radiation; alpha particles, beta particles and gamma photons. In particular, we are excluding non-ionising nuclear radiation in the form of neutrons, which definitely can turn previously stable nuclei into radioactive materials. This effect is a … Continue reading Does radiation make things radioactive?
Electron Capture and Internal Conversion
Having looked at some of the finer details for beta decay in two previous posts (Q-Value and Metastable Nuclei) it seems fitting to round-off this short series with two phenomena that involve orbiting electrons rather than just nucleons. The first effect is electron capture. As its name suggests, this is when an orbiting electron is … Continue reading Electron Capture and Internal Conversion
Technetium-99m
At first glance the decay of molybdenum-99 to produce technetium-99 is a straightforward beta process. The total number of nucleons is unchanged but the number of protons increases by one with the emission of an electron and an electron-antineutrino. The half-life for this decay is 66 hours. In the nuclear decay equation above, technetium-99 is … Continue reading Technetium-99m
Beta Decay Q-value
At GCSE level, beta decay is said to be the emission of an electron (or positron, in beta-plus decay) when an unstable nucleus transforms into a more stable nucleus. The parent and daughter nuclei are different elements with the same nucleon number (sum of neutrons and protons) but their proton numbers vary by +1 for … Continue reading Beta Decay Q-value
Beta Decay and Energy Conservation
I have just finished reading an excellent book that traces various theories about beta decay in the first third of the Twentieth Century. Controversy and Consensus: Nuclear Beta Decay 1911-1934 is an editted version of the successful PhD thesis written by Carsten Jensen, who clearly had a deep passion for unravelling physics history but died … Continue reading Beta Decay and Energy Conservation
How reliable are AI assistants?
To explore the current state of AI reliability in a physics context, two questions were put to five free AI assistants, all available via https://duck.ai/; Why don’t radioactive decay chains end with iron? Which isotope has the highest binding energy? Before revealing the AI responses, here are my own answers. Question 1 assumes that all … Continue reading How reliable are AI assistants?
How to Use Logarithms
Although they can seem confusing at first sight, logarithms are just mathematical functions that allow calculations to be carried out quicker than would otherwise be the case. So although they may seen daunting, you should think of logarithms as a way to make calculations easier – once you have mastered the rules. There is quite a … Continue reading How to Use Logarithms
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