1MA0 Higher November 2016 Paper 1 Q24
24 The intensity of the sound, \(I\) watts/m\(^2\), received from a loudspeaker is inversely proportional to the square of the distance, \(d\) metres, from the loudspeaker.
When \(d = 2\), \(I = 30\)
Work out the value of \(I\) when \(d = 10\) (3)
| Answer | Mark | Notes |
|---|---|---|
| 1.2 | 3 | M1 for \(I \propto \dfrac{1}{d^2}\) or \(I = \dfrac{k}{d^2}\) or \(k = Id^2\) or \(30 = \dfrac{k}{2^2}\) or \(k = 120\) M1 (dep) for \(I = \dfrac{\text{``}120\text{''}}{10^2}\) A1 cao |