Chapter 16: Temperature and HeatAnswers to Even-Numbered Conceptual Questions2. No. The Kelvin temperature is always 273.15 degrees greater than the Celsius temperature.4. No. Heat is not a quantity that one object has more of than another. Heat is the energy that is transferredbetween objects of different temperatures.6. In this case, the volume within the glass would increase more than the volume of the mercury wouldincrease. As a result, the mercury level would drop with increasing temperature.8. Heating the glass jar and its metal lid to the same higher temperature results in a greater expansion in the lidthan in the glass. As a result, the lid can become loose enough to turn.10. This could happen if the objects have the same mass but different specific heats. Similarly, it could happen ifthe objects have the same specific heat but different masses. Bottom line: The objects must have different heatcapacities.12. The soil in the field cools off faster than the concrete parking lot, because its temperature changes more for agiven amount of heat loss.14. Both the metal and the wood are at a lower temperature than your skin. Therefore, heat will flow from yourskin to both the metal and the wood. The metal feels cooler, however, because it has a greater thermalconductivity. This allows the heat from your skin to flow to a larger effective volume than is the case withthe wood.16. The answer is (e). That is, the only quantity in this list that does not affect the rate of heat flow is the specificheat of the slab.18. Updrafts are generally caused by different areas of the ground heating up at different rates on a sunny day.When skydiving, for example, it is common to experience more of an updraft when you are descending overa plowed field than when you are over a field of grass.20. The hollow fibers of hair are effective insulators because the gas within the fibers has a low thermalconductivity. This is analogous to double-pane windows, which trap a layer of gas between the panes for agreatly enhanced insulating effect.Solutions to Problems and Conceptual Exercises1. Picture the Problem: The coldest recorded temperature on Earth is given in degrees Celsius that need to be converted to Fahrenheit.Strategy: Use equation 16-1 to convert the temperature to Fahrenheit.Solution: Insert the temperature into equation 16-1: TF=95−89.2°C( )+32°F = −128.6°FInsight: This is below the freezing point of CO2, which is −109F.2. Picture the Problem: The temperature of an incandescent light bulb is given in Fahrenheit that needs to be converted toCelsius.Strategy: Use equation 16-2 to convert the temperature to Celsius. Copyright © 2010 Pearson Education, Inc. All rights reserved. This material is protected under all copyright laws as they currently exist. Noportion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.16 – 1Chapter 16: Temperature and Heat James S. Walker, Physics, 4th EditionSolution: Insert the temperature into equation 16-2: TC=594500°F −32°F( )= 2500°CInsight: For temperatures this large, the 32F shift is insignificant. The temperature in Celsius is essentially 5/9th of the reading in Fahrenheit.Copyright © 2010 Pearson Education, Inc. All rights reserved. This material is protected under all copyright laws as they currently exist. Noportion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.16 – 2Chapter 16: Temperature and Heat James S. Walker, Physics, 4th Edition3. Picture the Problem: The human body temperature is given in Fahrenheit that needs to be converted to Celsius and Kelvin.Strategy: Use equation 16-2 to convert the temperature to Celsius. Then use equation 16-3 to convert the result to Kelvin.Solution: 1. (a) Insert the temperature in °F into equation 16-2: TC=5998.6°F −32°F( )= 37.0°C2. (b) Insert the temperature in °C into equation 16-3: T =TC+273.15 K =37 K +273.15 K = 310.2 KInsight: A person is said to have a fever if her temperature is above 100F, which is 37.8C.4. Picture the Problem: A temperature is given in Kelvin that needs to be converted to Fahrenheit.Strategy: Solve equation 16-3 for the temperature in Celsius. Insert the result into equation 16-1 to write the temperature in Fahrenheit.Solution: 1. Convert from Kelvin to Celsius: TC=T −273.15°C2. Insert Tc into equation 16-1: TF=95T −273.15( )°C+32°F=951.0−273.15( )°C +32°F = −458°FInsight: Note that our answer is close to absolute zero (− 459.67 F), as expected, since 1 K is close to absolute zero.5. Picture the Problem: The temperature of the surface of the Sun is given in Kelvin and needs to be converted to Celsius and Fahrenheit.Strategy: Use equation 16-3 to convert the temperature to Celsius. Then insert the result into equation 16-1 to calculatethe temperature in Fahrenheit.Solution: 1. (a) Convert from Kelvin to Celsius: TC=T −273.15 K =6000 K −273.15 K = 5.7×103°C2. (b) Insert TC into equation 16-1: TF=955727°C( )+32°F = 1.0×104°FInsight: The surface of the Sun is greater than 10,000F!6. Picture the Problem: A temperature difference is given in Fahrenheit degrees and needs to be converted to Celsius degrees and to kelvins.Strategy: Write the temperature difference in Fahrenheit as a final temperature minus the initial temperature. Use equation 16-1 to write an equation to relate the temperature difference in Fahrenheit with the corresponding temperaturedifference in Celsius. Do the same with equation 16-3 to find the conversion between Celsius and Kelvin.Solution: 1. (a) Find the tem-perature difference in Celsius: ΔTC=TC2−TC1=59TF2−32°F( )−95TF1−32°F( )=59TF2−TF1( )=59ΔTFΔTC=5927°F( )=15°C2. (b) Find the temperature difference in Kelvin: ΔTK=TK 2−TK1= TC2+273.15( )− TC1+273.15( )ΔTK=TC2−TC1=ΔTC=15 KInsight: Since the Celsius degree and the Kelvin degree have the same size, a change in Celsius has the same magnitudeas the same change in Kelvin.Copyright © 2010 Pearson Education, Inc. All rights reserved. This material is protected under all copyright laws as they currently exist. Noportion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.16 – 3Chapter 16: Temperature and Heat James S. Walker, Physics, 4th EditionCopyright © 2010 Pearson
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