An electric immersion heater is put into a sample of water of mass m. The water is heated from its initial temperature T; (approximately room temperature) to a final temperature T; (less than 100°C) while the heater itself maintains a constant temperature To. The specific heat of water, c, remains constant throughout the process, and any heat transfer to the container and the environment is negligible. а. Can the temperature of the heater be compared to the final temperature of the water? If not, why not? If so, is To greater than, less than, or equal to Tf? Explain. b. In terms of the given quantities (m, c, T;, T, To) determine expressions for the entropy change of the water and the heater. С. Determine whether this process is reversible by analyzing the sign of the entropy change for the heater-and-water system. d. Explain conceptually in terms of the 2nd law why your result about reversibility from part (c) is correct.

An electric immersion heater is put into a sample of water of mass m. The water is heated from its initial temperature T; (approximately room temperature) to a final temperature T; (less than 100°C) while the heater itself maintains a constant temperature To. The specific heat of water, c, remains constant throughout the process, and any heat transfer to the container and the environment is negligible. а. Can the temperature of the heater be compared to the final temperature of the water? If not, why not? If so, is To greater than, less than, or equal to Tf? Explain. b. In terms of the given quantities (m, c, T;, T, To) determine expressions for the entropy change of the water and the heater. С. Determine whether this process is reversible by analyzing the sign of the entropy change for the heater-and-water system. d. Explain conceptually in terms of the 2nd law why your result about reversibility from part (c) is correct.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.8P

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