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10 (a) Stars may originate as a nebula - Edexcel - GCSE Physics - Question 10 - 2019 - Paper 1
Question 10
10 (a) Stars may originate as a nebula. (i) Describe the process that then occurs to produce the conditions necessary for nuclear fusion in a new star. (3) (ii) Th... show full transcript
Worked Solution & Example Answer:10 (a) Stars may originate as a nebula - Edexcel - GCSE Physics - Question 10 - 2019 - Paper 1
Step 1
Describe the process that then occurs to produce the conditions necessary for nuclear fusion in a new star.
Answer
The formation of a new star begins in a nebula, which is a vast cloud of gas and dust. As gravity pulls the material together, it begins to collapse, leading to an increase in density and temperature in the core of the forming star. This process can be summarized as follows:
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Gravitational Collapse: The nebula contracts under its own gravity, causing particles to come closer together. This increases the density and consequently raises the temperature due to gravitational potential energy being converted to thermal energy.
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Ignition of Fusion: As the temperature in the core rises, it eventually reaches the critical temperature necessary for nuclear fusion, which is about 10 million degrees Celsius. At this point, hydrogen nuclei begin to fuse into helium, releasing energy in the process.
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Hydrostatic Equilibrium: The energy produced by fusion exerts an outward pressure, balancing the inward pull of gravity, thus stabilizing the star in a state known as hydrostatic equilibrium.
Step 2
Calculate the loss in mass of the Sun in 1 second.
Answer
To calculate the loss of mass of the Sun due to the energy radiated in one second, we can use the relation from Einstein's theory of relativity:
egin{align*}
E & = mc^2
ext{where:}
E & = 3.86 imes 10^{26} ext{ J} \
m & = ext{loss in mass (kg)} \
c & = 3.00 imes 10^8 ext{ m/s}
d ext{Rearranging gives us:}\ m & = rac{E}{c^2} \ m & = rac{3.86 imes 10^{26}}{(3.00 imes 10^8)^2} \ m & = rac{3.86 imes 10^{26}}{9.00 imes 10^{16}} \ m & ext{Calculation yields:} \ m & eq 4.29 imes 10^{10} ext{ kg}
d ext{Thus, the loss in mass of the Sun in 1 second is approximately } 4.29 imes 10^{10} ext{ kg}.