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1.6 Exponentials and logarithms

1.6 Exponentials and logarithms

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Question 67

The surface area SSS, in mm2\text{mm}^2mm2, of a metallic crystal growing in a laboratory environment is monitored over time. The surface area is modelled by the equation

log⁡10S=0.85+0.072t \log_{10} S = 0.85 + 0.072t log10​S=0.85+0.072t

where t t\,t is the time in hours after the crystal began to form.

Use the equation of the model to answer parts (a) and (b).

a.

Find the initial surface area of the crystal, giving your answer to 2 decimal places.

[2]
b.

After T T\,T hours, the surface area reaches 120 mm2. Find the value of TTT, giving your answer to 2 decimal places.

[3]
Markscheme

1.6 Exponentials and logarithms Questions

  1. A Level
  2. /Maths
  3. /1.6 Exponentials and logarithms

104 exam-style questions on WJEC A Level Maths 1.6 Exponentials and logarithms, covering 1.6.1 Exponentials and logarithms, 1.6.2 Exponentials and logarithms, 1.6.3 Exponentials and logarithms, 1.6.4 Exponentials and logarithms, 1.6.5 Exponentials and logarithms, 1.6.6 Exponentials and logarithms, 1.6.7 Exponentials and logarithms, 1.6.8 Exponentials and logarithms, and 1.6.9 Exponentials and logarithms. Each one has a worked solution and a mark scheme showing where the marks go.

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