A few days ago someone posted asking for help understanding AC. Apart from ridiculing the username there were few replies. I wonder why?
That's not quite true.
I did say that some posters including yourself offered further help.
You, yourself linked to an explanation which was far more involved than even Eric or John would bother typing. For a subject and question like that, exploring Google would seem to be far more productive.
My point exactly - the depth of understanding required for the DIY poster to complete a safe and satisfactory task is not the same as a complete understanding of underlying principles. I'm not complaining that people did not try to help the AC poster- the suggestion of google is fine and a DIY forum is not the place for explanations of advanced physics. My key point was that to require a "genuine understanding" needs qualifying in the context. I am not against people being told that they need to understand the necessary circuit/safety/etc principles of the task undertaken nor to be advised to stop and get qualified advice. The question to ask is, "What do we want to achieve?" and the pragmatic instructions are more likely to give a safe outcome than a 'go and read' command where the poster may feel insulted, not have a good reading ability or be under pressure to finish the task.
Please explain the situation in the Middle East. A good example; this was used many years ago as an example of how not to write examination questions. The student could write, "I cannot explain the the situation in the Middle East". It would be 100% honest, 100% correct and therefore deserves 100% marks. Just like the unqualified genuine understanding comment the failure to properly explain what was required makes a nonsense of question and answer.
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