Concept explainers
(a)
The mass density of
Answer to Problem 34Q
The mass density of radiation is
Explanation of Solution
Given:
The temperature of the photosphere of the Sun is,
The average density of matter is
Formula Used:
The mass density of radiation is given by,
Here,
Calculation:
The mass density of radiation is calculated as,
The mass density of radiation is less than the average density of matter. Therefore, the radiation is matter-dominated.
Conclusion:
The mass density of radiation is
(b)
The mass density of radiation of the centre of the Sun and to explain whether the radiation is matter-dominated or radiation-dominated.
Answer to Problem 34Q
The mass density of radiation is
Explanation of Solution
Given:
The temperature of the centre of the Sun is,
The average density of matter is
Formula Used:
The mass density of radiation is given by,
Here,
Calculation:
The mass density of radiation is calculated as,
The mass density of radiation is less than the average density of matter. Therefore, the radiation is matter-dominated.
Conclusion:
The mass density of radiation is
(c)
The mass density of radiation of the solar corona and to explain whether the radiation is matter-dominated or radiation-dominated.
Answer to Problem 34Q
The mass density of radiation is
Explanation of Solution
Given:
The temperature of the solar corona is,
The average density of matter is
Formula Used:
The mass density of radiation is given by,
Here,
Calculation:
The mass density of radiation is calculated as,
The mass density of radiation is more than the average density of matter. Therefore, the radiation is radiation-dominated.
Conclusion:
The mass density of radiation is
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Chapter 25 Solutions
Universe: Stars And Galaxies
- The text says that the Local Fluff, which surrounds the Sun, has a temperature of 7500 K and a density 0.1 atom per cm3. The Local Fluff is embedded in hot gas with a temperature of 106 K and a density of about 0.01 atom per cm3. Are they in equilibrium? (Hint: In pressure equilibrium, the two regions must have nT equal, where n is the number of particles per unit volume and T is the temperature.) What is likely to happen to the Local Fluff?arrow_forwardIf the emitted infrared radiation from Pluto, has a wavelength of maximum intensity at 75,000 nm, what is the temperature of Pluto assuming it follows Wien’s law?arrow_forwardTable 15.1 indicates that the density of the Sun is 1.41 g/cm3. Since other materials, such as ice, have similar densities, how do you know that the Sun is not made of ice?arrow_forward
- Now suppose that all of the hydrogen atoms in the Sun were converted into helium. How much total energy would be produced? (To calculate the answer, you will have to estimate how many hydrogen atoms are in the Sun. This will give you good practice with scientific notation, since the numbers involved are very large! See Appendix C for a review of scientific notation.)arrow_forwardShow that the statement that 92% of the Sun’s atoms are hydrogen is consistent with the statement that 73% of the Sun’s mass is made up of hydrogen, as found in Table 15.2. (Hint: Make the simplifying assumption, which is nearly correct, that the Sun is made up entirely of hydrogen and helium.)arrow_forwardWhy do you suppose so great a fraction of the Sun’s energy comes from its central regions? Within what fraction of the Sun’s radius does practically all of the Sun’s luminosity originate (see Figure 16.16)? Within what radius of the Sun has its original hydrogen been partially used up? Discuss what relationship the answers to these questions bear to one another. Figure 16.16 shows how the temperature, density, rate of energy generation, and composition vary from the center of the Sun to its surface.arrow_forward
- Our sun is a standard sequence yellow dwarf star with a temperature of about 6000 K and a radius of about 7 x 10^8 m, emitting about 3.8 x 10^26 W. There are yellow giant stars with the same blackbody color (temperature) but with a radius 10 times larger than our sun (7 x 10^9 m). Estimate the power (emitted radiation) from one of these yellow giant stars. (Hint: how much larger is the surface area of the yellow giant star, and pay careful attention to the power of 10 below.)arrow_forwardCalculate the heat of fusion using the data provided and the equation in the red box.arrow_forwardWhat does the Wien Displacement Law (also known as Wien's Law) tell us? a) There is an inverse relation between the temperature of a thermal emitter and the wavelength where the emission peaks. b) There is a proportional relation between the temperature of a thermal emitter and the wavelength where the emission peaks. c) None of the above.arrow_forward
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