1.6 Exponentials and logarithms

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Question 59

The concentration $C$ (in mg/L) of a bioactive compound in a chemical reactor is modelled by the equation

C = pq^t

where $p$ and $q$ are constants and $t$ is the time in hours since the reaction began.

The relationship between $t$ and $log_{10} C$ is linear. The graph of this relationship passes through the vertical intercept $(0, 1.48)$ and the point $(25, 0.73)$ .

Find an equation for this line in the form $log_{10} C = mt + c$ .

[2]

Find the value of $p$ and the value of $q$ , giving your answers to 3 significant figures.

[2]

According to the model, find the value of $t$ when the concentration reaches 10 mg/L.

[2]

1.6 Exponentials and logarithms Questions

A Level
Maths
1.6 Exponentials and logarithms

A Level
Maths WJEC
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