The illustration below is used to produce a measured rise in temperature of a liquid using electrical energy. Explain why; i) The liquid will tend to be...

The illustration below is used to produce a measured rise in temperature of a liquid using electrical energy.

Explain why;
i) The liquid will tend to be warmer at the top of the container than at the bottom.
ii) The temperature will eventually stop rising even though the current is still passing through the heating coil.
iii) If the apparatus is used to determine the specific heat capacity of the liquid, the accuracy of the experiment will be increased if the liquid is first cooled to about 5^oc below room temperature and the current passed until the temperature is about 5^oc above room temperature.

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i) Hot water is less dense and thus rises to the top due to convectional current.
ii) The liquid has reached its boiling point
iii) Heat losses are minimized as follows:
When 5^oc below room temperature heat is gained; when 5^oc above room temperature, the same amount of heat previously gained is now lost. Thus the net heat exchange is zero

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Kavungya answered the question on May 31, 2019 at 10:03

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