/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 35 (a) A deuteron, \(^{2}_{1} \math... [FREE SOLUTION] | 91Ó°ÊÓ

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(a) A deuteron, \(^{2}_{1} \mathrm{H},\) is the nucleus of a hydrogen isotope and consists of one proton and one neutron. The plasma of deuterons in a nuclear fusion reactor must be heated to about 300 million \(\mathrm{K}\). What is the ms speed of the deuterons? Is this a significant fraction of the speed of light \(\left(c=3.0 \times 10^{8} \mathrm{m} / \mathrm{s}\right) ?\) (b) What would the temperature of the plasma be if the deuterons had an ms speed equal to 0.10\(c ?\)

Short Answer

Expert verified
(a) The rms speed is approximately 1.07 million m/s, about 0.0036 of light speed. (b) For 0.10c speed, temperature is about 2.01 billion K.

Step by step solution

01

Understanding the Problem

We need to calculate the rms (root mean square) speed of deuterons at 300 million K and determine if this is a significant fraction of the speed of light. Then, we need to find the temperature needed for the deuterons to move at 0.10c.
02

Use the Formula for rms Speed

The rms speed of particles in an ideal gas is given by the formula \( v_{rms} = \sqrt{\frac{3kT}{m}} \) where \( k \) is Boltzmann's constant \( 1.38 \times 10^{-23} \mathrm{J/K} \), \( T \) is the temperature in Kelvin, and \( m \) is the mass of a deuteron. The mass of a deuteron is approximately \( 3.34 \times 10^{-27} \mathrm{kg} \).
03

Calculate rms Speed at 300 Million K

Plugging in the values, we have \( v_{rms} = \sqrt{\frac{3 \times 1.38 \times 10^{-23} \times 3 \times 10^{8}}{3.34 \times 10^{-27}}} \). Calculating this gives \( v_{rms} \approx 1.07 \times 10^6 \, \mathrm{m/s} \).
04

Check the Fraction of the Speed of Light

The fraction of the speed of light is \( \frac{1.07 \times 10^6}{3.0 \times 10^8} \approx 0.00357 \). This is significantly less than 1, indicating it's a small fraction of the speed of light.
05

Calculate Temperature for rms Speed of 0.10c

To find the temperature for \( v_{rms} = 0.10c = 3 \times 10^7 \, \mathrm{m/s} \), use the formula \( T = \frac{mv_{rms}^2}{3k} \). Substituting the values, \( T = \frac{3.34 \times 10^{-27} \times (3 \times 10^7)^2}{3 \times 1.38 \times 10^{-23}} \), which results in \( T \approx 2.01 \times 10^9 \, \mathrm{K} \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Root Mean Square Speed
The root mean square (rms) speed is an important concept in understanding the behavior of particles in a gas. It gives us a measure of the average speed of particles at a given temperature. In mathematical terms, the rms speed is represented as:
  • \( v_{rms} = \sqrt{\frac{3kT}{m}} \)
Here, \( k \) is Boltzmann's constant, \( T \) is the temperature in Kelvin, and \( m \) is the mass of the particle.
This formula allows us to relate the speed of particles to the temperature of the system. In essence, it tells us how quickly particles are moving on average due to thermal energy. Rms speed helps in understanding how energetic particles are in a gas cloud, which is crucial in fields like thermodynamics and kinetic theory of gases. When applied to the plasma in nuclear fusion, understanding rms speed is essential to controlling reactions and ensuring they are efficient and stable.
Deuteron
Deuterons are the nuclei of deuterium, an isotope of hydrogen. Deuterium consists of one proton and one neutron. As a result, deuterons have twice the mass of a simple hydrogen nucleus.
This extra mass plays a significant role when calculating the behavior of deuterons in a plasma environment. For example, we consider their mass when determining how they move under thermal energy. The presence of deuterons in nuclear fusion reactors is common because they can participate in fusion reactions effectively. They are used to achieve temperatures high enough for fusion energy production. Thus, understanding the properties of deuterons, such as their mass and how they interact at high temperatures, is key to advancing fusion technology.
Plasma Temperature
Plasma temperature is a crucial factor in nuclear fusion reactors, as it determines the energy and speed of the charged particles. In the context of nuclear fusion, the temperature must be extremely high, often reaching millions of Kelvin.
This high temperature is necessary to overcome the electrostatic repulsion between nuclei, allowing them to come close enough to potentially fuse. In the exercise provided, the plasma needs to be heated to 300 million Kelvin to reach a state where deuterons can freely collide and possibly fuse. At such high temperatures, particles achieve significant speeds, which is why we calculate their rms speed. Understanding plasma temperatures helps us design and operate reactors that can maintain the right conditions for sustained and efficient fusion.
Boltzmann's Constant
Boltzmann's constant \( (k) \) is a fundamental constant in physics that relates the average kinetic energy of particles in a gas with the temperature of the gas. It has a value of approximately \( 1.38 \times 10^{-23} \, \mathrm{J/K} \).
This constant serves as the bridge between macroscopic and microscopic physical systems, enabling us to relate temperature (a macroscopic property) to kinetic energy (a microscopic property).In calculating rms speed, Boltzmann's constant provides the necessary link to determine how fast particles, like deuterons in a plasma, move at a given temperature.
Understanding this relationship is vital for fields that study the dynamical behavior of gases and plasmas. It emphasizes the importance of temperature and how it governs the motion and interactions of particles in a system. Boltzmann's constant also plays an essential role in statistical mechanics, helping to describe how systems behave at a fundamental level.

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Most popular questions from this chapter

A cylinder 1.00 \(\mathrm{m}\) tall with inside diameter 0.120 \(\mathrm{m}\) is used to hold propane gas (molar mass 44.1 \(\mathrm{g} / \mathrm{mol}\) ) for use in a barbecue. It is initially filled with gas until the gauge pressure is \(1.30 \times 10^{6} \mathrm{Pa}\) and the temperature is \(22.0^{\circ} \mathrm{C} .\) The temperature of the gas remains constant as it is partially emptied out of the tank, until the gauge pressure is \(2.50 \times 10^{5}\) Pa. Calculate the mass of propane that has been used.

The speed of propagation of a sound wave in air at \(27^{\circ} \mathrm{C}\) is about 350 \(\mathrm{m} / \mathrm{s}\) . Calculate, for comparison, (a) \(v_{\mathrm{ms}}\) for nitrogen molecules and (b) the rms value of \(v_{x}\) at this temperature. The molar mass of nitrogen \(\left(\mathrm{N}_{2}\right)\) is \(28.0 \mathrm{g} / \mathrm{mol} .\)

You have several identical balloons. You experimentally determine that a balloon will break if its volume exceeds 0.900 \(\mathrm{L}\). The pressure of the gas inside the balloon equals air pressure \((1.00 \mathrm{atm} \). (a) If the air inside the balloon is at a constant temperature of \(22.0^{\circ} \mathrm{C}\) and behaves as an ideal gas, what mass of air can you blow into one of the balloons before it bursts? (b) Repeat part (a) if the gas is helium rather than air.

A person at rest inhales 0.50 \(\mathrm{L}\) of air with each breath at a pressure of 1.00 atm and a temperature of \(20.0^{\circ} \mathrm{C}\) . The inhaled air is 21.0\(\%\) oxygen. (a) How many oxygen molecules does this person inhale with each breath? (b) Suppose this person is now resting at an elevation of \(2,000 \mathrm{m}\) but the temperature is still \(20.0^{\circ} \mathrm{C}\). Assuming that the oxygen percentage and volume per inhalation are the same as stated above, how many oxygen molecules does this person now inhale with each breath? (c) Given that the body still requires the same number of oxygen molecules per second as at sea level to maintain its functions, explain why some people report "shortness of breath" at high elevations.

Consider 5.00 mol of liquid water. (a) What volume is occupied by this amount of water? The molar mass of water is 18.0 \(\mathrm{g} / \mathrm{mol}\) (b) Imagine the molecules to be, on average, uniformly spaced, with each molecule at the center of a small cube. What is the length of an edge of each small cube if adjacent cubes touch but don't overlap? (c) How does this distance compare with the diameter of a molecule?

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