Study Fig. 4, which is a table for calculating relative humidity from wet bulb and dry bulb temperature readings. [Figure 4 is a table showing dry bulb temperature (°C) against difference between wet bulb and dry bulb temperatures (°C), with relative humidity (%) values. Values are provided for dry bulb temperatures from 0 to 16°C and differences from 0 to 12°C.]

1. (a)(i)What is a wet bulb thermometer?[1]
2. (a)(ii)Why is the wet and dry bulb thermometer sited in a Stevenson screen?[2]
3. (b)(i)What is the relative humidity when there is no difference between the wet bulb and dry bulb temperature readings? %[1]
4. (b)(ii)Calculate the relative humidity when the dry bulb reading is 12°C and the wet bulb reading is 9°C. Show your working.[2]
5. (c)Which instruments could be kept in a Stevenson screen. Circle two correct answers. anemometer barometer maximum-minimum thermometer rain gauge wind vane[2]

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