Holooly Plus Logo
Holooly Plus Logo

Question 2.171: Thermos Bottle. (a) State and justify how the thermal conduc...

Thermos Bottle.

(a) State and justify how the thermal conductivity of an ideal gas depends on its density at fixed temperature.

(b) A thermos (Dewar) bottle is constructed of two concentric glass vessels with the air in the intervening space reduced to a low density. Why can it act as an insulating container even though the vacuum is not perfect?

The "Step-by-Step Explanation" refers to a detailed and sequential breakdown of the solution or reasoning behind the answer. This comprehensive explanation walks through each step of the answer, offering you clarity and understanding.
Our explanations are based on the best information we have, but they may not always be right or fit every situation.
The blue check mark means that this solution has been answered and checked by an expert. This guarantees that the final answer is accurate.
Learn more on how we answer questions.
This Question has been Answered.
Subscribe
Already have an account?
Login

Related Answered Questions

Question: 2.165

Radiation pressure. One may think of radiation as a gas of photons and apply many of the results from kinetic theory and thermodynamics to the radiation gas. (a) Prove that the pressure exerted by an isotropic radiation field of energy density u on a perfectly reflecting wall is p = u/3. ...

Verified Answer:

(a) Consider an area element dS of the perfectly r...
Question: 2.163

A system consists of N very weakly interacting particles at a temperature sufficiently high such that classical statistics are applicable. Each particle has mass m and oscillates in one direction about its equilibrium position. Calculate the heat capacity at temperature T in each of the following ...

Verified Answer:

According to the virial theorem, if the potential ...
Question: 2.162

Starting with the virial theorem for an equilibrium configuration show that: (a) the total kinetic energy of a finite gaseous configuration is equal to the total internal energy if γ = Cp /Cv = 5/3 , where Cp and Cv are the molar specific heats of the gas at constant pressure and at constant volume ...

Verified Answer:

For a finite gaseous configuration, the virial the...
Question: 2.161

A box of volume 2V is divided into halves by a thin partition. The left side contains a perfect gas at pressure p0 and the right side is initially vacuum. A small hole of area A is punched in the partition. What is the pressure p 1 in the left hand side as a function of time? Assume the temperature ...

Verified Answer:

Because the hole is small, we can assume the gases...
Question: 2.166

A gas of interacting atoms has an equation of state and heat capacity at constant volume given by the expressions p(T,V )= aT^1/2 + bT^3 + c V ^- 2, Cv(T, V)= dT^1/2V + eT^2V + fT^1/2, where a through f are constants which are independent of T and V . (a) Find the differential of the internal ...

Verified Answer:

\text { (a) We have } d U(T, V)=C_{v} d T+\...
Question: 2.169

(a) Assuming moderately dilute helium gas so that binary collisions of helium atoms determine the transport coefficients] derive an expression for the thermal conductivity of the gas. (b) Estimate the ratio of the thermal conductivity of gaseous ^3He to that of gaseous ^4He at room temperature. ...

Verified Answer:

(a) Consider an area element dS of an imaginary pl...
Question: 2.170

A certain closed cell foam used as an insulating material in houses is manufactured in such a way that the cells are initially filled with a polyatomic gas of molecular weight ∼60. After several years the gas diffuses out of the foam and is replaced by dry air (mean molecular weight ...

Verified Answer:

The thermal conductivity is \kappa \sim \la...
Question: 2.172

Sketch the temperature dependence of the heat conductivity of an insulating solid. State the simple temperature dependencies in limiting temperature ranges and dervie them quantitatively. ...

Verified Answer:

The thermal conductivity of a solid is \kap...
Question: 2.168

(a) Show that the ratio of the pressure to the viscosity coefficient gives approximately the number of collisions per unit time for a molecule in a gas. (b) Calculate the number of collisions per unit time for a molecule in a gas at STP using the result of (a) above or by calculating it from the ...

Verified Answer:

(a) The coefficient of viscosity is \eta=\f...
Question: 2.164

By treating radiation in a cavity as a gas of photons whose energy ε and momentum k are related by the expression ε = ck, where c is the velocity of light, show that the pressure p exerted on the walls of the cavity is one-third of the energy density. With the above result prove that when radiation ...

Verified Answer:

Let n(\omega) d \omega denote the n...