Question 998792
You really mean, {{{d=10*ln(I/I[o])}}}.


After that, your items to answer are incomplete.  You show a given I value, but your needed {{{I[o]}}} value is missing or something.  Maybe, you mean it they way they look.  Not sure.


(A)
The log input seems to be   {{{I*I[o]/I[o]}}}.  It just looks strange.  This would mean, {{{d=10*ln(2500)}}}
{{{d=10*7.8}}}
{{{highlight(d=78)}}}.


The rest of your items are all of the same form and so you will treat them the same way.  (Item E is different but only relies on good judgement about avoiding damaging noise).


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Recheck your given formula for d.
Factor of 10, factor of Natural Logarithm of (I divided by I sub zero).
The question part (A) gives you  I equals 2500 multiplied by I sub zero.  This will mean  (you recheck the arithmetic or the algebra) that your expression to evaluate is  :  Factor of 10, factor of Natural Logarithm of 2500.


Use scientific calculator, or graphing calculator, or table of logarithms.
{{{ln(2500)}}}
{{{ln(25)+ln(100)}}}
{{{ln(25)+ln(1*10^2)}}}
{{{ln(25)+ln(1)+ln(10^2)}}}
{{{ln(25)+0+2*ln(10)}}}
{{{3.2189+2*2.3026}}}
{{{highlight_green(7.8241)}}}
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NOW, be reminded, the exprssion you want to compute is  {{{10*ln(2500)}}}
{{{10*7.8241}}}
{{{78.241}}}
Best is to keep with just two significant figures here because that is the best accuracy that you have in the given data, so,
{{{highlight(78)}}}.



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For B, C, and D, JUST FOLLOW THE FORMULA.


C,
{{{d=10*ln(I/I[o])}}}
{{{d=10*ln(2500000)}}}
{{{d=10*14.7318}}}
{{{d=150}}}--------------or 147, if to three significant figures