| Date | May 2012 | Marks available | 2 | Reference code | 12M.1.sl.TZ2.6 |
| Level | SL only | Paper | 1 | Time zone | TZ2 |
| Command term | Calculate | Question number | 6 | Adapted from | N/A |
Question
Water has a lower boiling point at higher altitudes. The relationship between the boiling point of water (T) and the height above sea level (h) can be described by the model \(T = -0.0034h +100\) where T is measured in degrees Celsius (°C) and h is measured in metres from sea level.
Write down the boiling point of water at sea level.
Use the model to calculate the boiling point of water at a height of 1.37 km above sea level.
Water boils at the top of Mt. Everest at 70 °C.
Use the model to calculate the height above sea level of Mt. Everest.
Markscheme
100 °C (A1) (C1)
[1 mark]
\(T = -0.0034 \times 1370 + 100\) (A1)(M1)
Note: Award (A1) for 1370 seen, (M1) for substitution of their h into the equation.
95.3 °C (95.342) (A1) (C3)
Notes: If their h is incorrect award at most (A0)(M1)(A0). If their h = 1.37 award at most (A0)(M1)(A1)(ft).
[3 marks]
\(70 = -0.0034h + 100\) (M1)
Note: Award (M1) for correctly substituted equation.
h = 8820 m (8823.52...) (A1) (C2)
Note: The answer is 8820 m (or 8.82 km.) units are required.
[2 marks]
Examiners report
The majority of the candidates showed they were able to substitute values into the model. The most common mistake was to neglect converting 1.37 km into metres. Some candidates did not appreciate the practical considerations of this question; Mount Everest will never be less than one metre high. It is important to remind students to check their answers in terms of the context of the information given.
The majority of the candidates showed they were able to substitute values into the model. The most common mistake was to neglect converting 1.37 km into metres. Some candidates did not appreciate the practical considerations of this question; Mount Everest will never be less than one metre high. It is important to remind students to check their answers in terms of the context of the information given.
The majority of the candidates showed they were able to substitute values into the model. The most common mistake was to neglect converting 1.37 km into metres. Some candidates did not appreciate the practical considerations of this question; Mount Everest will never be less than one metre high. It is important to remind students to check their answers in terms of the context of the information given.
