How do you calculate this problem (physics)?
The dismantling of a reactor pressure vessel involves high radiation exposure for workers because the material has become highly radioactive due to neutron radiation during operation. A large portion of this activity comes from the cobalt isotope 60Co (half-life TH = 5.27 years).
a) According to model calculations, the inside of the reactor pressure vessel has a 60Co activity of 1.0 105 Bq per gram of steel. Calculate the time required for this activity to decrease to 10 Bq per gram of steel.
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I assume that with “1.0 · 105 Bq” more 1.0 ⋅ 105 Bq instead of 1.0 ⋅ 105 Bq is meant, right?
With the disintegration equation
with the initial activity of A0 = 1.0 ⋅ 105 Bq and half-life T_H = 5,27 a and activity A(t) = 10 Bq t by calculating the equation t and the given values are used.
The time required is therefore about 70 years.
I’m sorry about the stupid question, but what is that for? I know, but I don’t know
“ln” is the natural logarithm.
https://de.wikipedia.org/wiki/Logarithmus#Natural_Logarithmus
Instead of this, you can also use a logarithm to any other base. That works the same way here. You could, for example…
t = lg((10 Bq)/(1,0 ⋅ 105 Bq)/lg(1/2) · 5,72 a ≅ 70 a
… with the decadic logarithm (to base 10) or, for example, …
t = log2((10 Bq)/(1,0 ⋅ 105 Bq)/log2(1/2) · 5,72 a ≅ 70 a
… with the logarithm to base 2.
The “l” in “ln” not only looks like a small L/l, it is a small L/l! It’s not a big I/i.
L/l as the initial letter of the word ‘logarithm’.
Thanks, I looked like a L, so I was so confused. Thanks for clarification!