Concept explainers
(a)
The mass density of
(a)
Answer to Problem 34Q
Solution:
Mass density of radiation at the photosphere of the Sun is,
Explanation of Solution
Given data:
Temperature at the photosphere of the Sun,
Average density of matter at the photosphere of the Sun,
Formula used:
Write the expression for mass density of radiation.
Here,
Explanation:
Energy in the entire universe usually falls into two categories – matter or radiation. To calculate the weightage of matter and radiation in the energy, we find the mass density of the radiation, which is equivalent to the mass of the entire radiation divided by the volume in which that radiation is contained. If the value of mass density of the radiation comes out less than the average density of matter, then the radiation is matter-dominated, otherwise, it is radiation-dominated. Refer to the expression for mass density of radiation.
Substitute
Conclusion:
Hence, the radiation at the photosphere of the Sun is matter-dominated and value of its mass density is,
(b)
The mass density of radiation
(b)
Answer to Problem 34Q
Solution:
Mass density of radiation at the center of the Sun,
Explanation of Solution
Given data:
Temperature at the center of the Sun,
Average density of matter at the center of the Sun,
Formula used:
Write the expression for mass density of radiation.
Here,
Explanation:
As per Einstein’s law of mass-energy equivalence, that is,
Substitute
Conclusion:
Hence, the radiation at the center of the Sun is matter-dominated as the value of its mass density is,
(c)
The mass density of radiation
(c)
Answer to Problem 34Q
Solution:
Mass density of radiation at the solar corona,
Explanation of Solution
Given data:
Temperature at the corona of the Sun,
Average density of matter at the corona of the Sun,
Formula used:
Write the expression for mass density of radiation.
Here,
Explanation:
According to the mass-energy relation of Einstein,
Substitute
Conclusion:
Hence, the value of mass density of radiation at the solar corona is,
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Chapter 25 Solutions
Universe
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