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    Hi everyone,

    Can anyone help with question 14.a)iii). I understand the photons per second is worked out by calculating useful power output/E of one proton. However, on the mark scheme it shows the power output as 3x10^-3. I don't understand how they have gone from 3mW to 3x10^-3 W... surely it would be 3x10^6 W? Although when I use this value, I get an energy efficiency of around 652000% which proves I am making the mistake, I just don't see where...

    Thanks

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    (Original post by danielcb12)
    Hi everyone,

    Can anyone help with question 14.a)iii). I understand the photons per second is worked out by calculating useful power output/E of one proton. However, on the mark scheme it shows the power output as 3x10^-3. I don't understand how they have gone from 3mW to 3x10^-3 W... surely it would be 3x10^6 W? Although when I use this value, I get an energy efficiency of around 652000% which proves I am making the mistake, I just don't see where...

    Thanks

    Name:  Exam Q.png
Views: 64
Size:  13.9 KB

    Attachment 524701524713
    http://astro.unl.edu/classaction/tab..._prefixes.html

    prefix of m (lower case) means milli i.e. 10^-3
    prefix of M (upper case) means mega i.e. 10^6
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    (Original post by Joinedup)
    http://astro.unl.edu/classaction/tab..._prefixes.html

    prefix of m (lower case) means milli i.e. 10^-3
    prefix of M (upper case) means mega i.e. 10^6

    Thank you! Seems so obvious now!
 
 
 
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