Math Problem Statement

The temperature and pressure around the surface of a star are 9.02 × 10^5 K and 0.0478 Pa. Calculate the rms speed of free electrons (mass = 9.11 × 10^-31 kg) there, assuming they are an ideal gas.

Solution

The root mean square (rms) speed of a particle in an ideal gas can be calculated using the formula:

vrms=3kBTmv_{rms} = \sqrt{\frac{3k_B T}{m}}

Where:

  • kBk_B is the Boltzmann constant (1.38×1023J/K1.38 \times 10^{-23} \, \text{J/K}),
  • TT is the temperature (9.02×105K9.02 \times 10^5 \, \text{K}),
  • mm is the mass of the particle (9.11×1031kg9.11 \times 10^{-31} \, \text{kg}).

Let's compute:

  1. Calculate the numerator: 3kBT3k_B T: 3kBT=3×(1.38×1023)×(9.02×105)3k_B T = 3 \times (1.38 \times 10^{-23}) \times (9.02 \times 10^5)

  2. Divide by the mass mm: 3kBTm\frac{3k_B T}{m}

  3. Take the square root to find vrmsv_{rms}.

Let me calculate this for you. math

Constants

k_B = 1.38e-23 # Boltzmann constant in J/K T = 9.02e5 # Temperature in K m = 9.11e-31 # Mass of the electron in kg

Calculate the rms speed

v_rms = math.sqrt((3 * k_B * T) / m) v_rmsThe root mean square (rms) speed of the free electrons is approximately 6.40×106m/s6.40 \times 10^6 \, \text{m/s}.

Let me know if you would like more details or have any questions.

Here are 5 questions to expand your understanding:

  1. How is the Boltzmann constant related to thermodynamic systems?
  2. What is the significance of the rms speed in ideal gas behavior?
  3. How does temperature affect the rms speed of particles?
  4. Can the pressure in the problem be used to cross-check results?
  5. How does the mass of the particle influence its rms speed?

Tip: Always double-check your units when using equations involving physical constants to avoid errors.

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Math Problem Analysis

Mathematical Concepts

Kinetic Theory of Gases
Thermodynamics
Root Mean Square Speed

Formulas

v_rms = sqrt(3k_B T / m)

Theorems

Kinetic theory relation for particle motion in an ideal gas

Suitable Grade Level

College-level Physics or Advanced High School Physics