Two test tubes with water are heated by a candle flame as shown in Fig. 7.16. Which thermometers (Fig. 7.16a or Fig. 7.16b) Class 7
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Two test tubes with water are heated by a candle flame as shown in Fig. 7.16. Which thermometers (Fig. 7.16a or Fig. 7.16b) Class 7
Two test tubes with water are heated by a candle flame as shown in Fig. 7.16. Which thermometers (Fig. 7.16a or Fig. 7.16b) will record a higher temperature? Explain. Class 7
Answer:
Fig. (a): The candle flame heats the bottom of the test tube; thermometer is placed at the top of the test tube and directly. The water at the bottom gets heated and rises due to convection, carrying heat to the top, where the thermometer is placed. So, the thermometer quickly records a temperature rise.
Fig. (b): The candle flame heats the side of the test tube, which may not be as effective in transferring heat to the bottom where the thermometer is placed.
Therefore, the thermometer in Fig. (a) will record a higher temperature.