Question

3. Explain why it is necessary to calibrate the spectroscope, and briefly outline the procedure that you will use to do this. An example of a calibration process is the following: Thermocouples can be used to measure temperature when it is not practical to do so with a thermometer. Thermocouples measure temperature in terms of voltage, rather than directly on a temperature scale and therefore need to be calibrated. Comparing the thermocouple output with the reading from a highly accurate thermometer allows the correlation between voltage and temperature. Based on the calibration curve below, what is the temperature of a substance measured with a thermocouple reading of 0.498 V? Thermocouple Calibration 50 45 y+49.532x+16.443 R2 0.9922 40 0.30 0.36 040 0.48 0.50 0.6 0.60 0.65 0.70 0.75 Thermocouple Voltage, V 30

Answer 1

calibraton is required to find out if the temperature and voltage correlation is varying linearly or not. once the calibration plot is done it will eliminate the error that might occur due to direct measurement of temperature from voltage. that is why the calibration curve is a best fit mean curve. at different pont the voltage is recorded and the temperature is correlated with it. the best fit curve is then drawn. then the voltage can be recorded and placed to the curve and find out the temperature and then matched to that of thermometer.

thermocouple readind is 0.498V. voltage is poltted in x axis. so x = 0.498

temperature is in y axis. hence temperature = y = (49.532*0.498)+16.443 = 41.109936 degree Celcius.