In order to calculate the heat loss through the wall of a building, it is necessary to know the temperature difference between inside and outside walls. Temperatures of 5 and 20C are measured on each side of the wall by mercury-in-glass thermometers with a range of 0 to +50C and a quoted inaccuracy of1% of full-scale reading. (a) Calculate the likely maximum possible eror in the calculated value for the temperature difference. (b) Discuss briefly how using measuring instruments with a different measurement range may improve measurement accuracy.