What is the mean photon energy of.......?
During the history of the Universe from the Big Bang to the present day, at some point in time the mean temperature of the Universe was 1 × 10^17 K. What was the mean photon energy at this instant, and which of the four fundamental interactions or three unified interactions were in evidence at this time?
what is the mean photon energy,please write it in scientific notation to a precision of one significant figure,
The mean photon energy was = ??? eV
which of the following would also indicate which interactions were in evidence:
1. electromagnet interaction
2. weak interaction
3. strong interaction
4. gravitational interaction
5. electroweak unification
6. Grand unification
7. superunification
It's about 9*10^12 eV. The temperature where electroweak symmetry breaking occurs happens at about 90 GeV, so at about 10^15 K.
3 x 10 2
To calculate the mean photon energy, we can use the relationship between temperature and photon energy. The mean photon energy can be expressed using the Boltzmann constant, k, and the temperature, T, as follows:
E_mean = k * T
First, we need to convert the given temperature, 1 × 10^17 K, into the corresponding energy units. The Boltzmann constant is approximately 8.6173 × 10^-5 eV/K.
E_mean = (8.6173 × 10^-5 eV/K) * (1 × 10^17 K)
= 8.6173 × 10^12 eV
So, the mean photon energy at this instant is approximately 8.6173 × 10^12 eV.
Now, let's consider which interactions were in evidence at this time. Based on the given information, we need to determine which of the four fundamental interactions or three unified interactions were present.
The four fundamental interactions are:
1. Electromagnetic interaction: This interaction is responsible for electromagnetic forces like light, electricity, and magnetism.
2. Weak interaction: This interaction is involved in radioactive decay and neutrino interactions.
3. Strong interaction: This interaction is responsible for holding atomic nucleons (protons and neutrons) together in the nucleus.
4. Gravitational interaction: This interaction is responsible for the force of gravity.
The three unified interactions are:
5. Electroweak unification: This unified interaction combines the electromagnetic and weak interactions under high-energy conditions.
6. Grand unification: This unified interaction combines the strong, electromagnetic, and weak interactions under very high-energy conditions.
7. Superunification: This hypothetical unified interaction combines all four fundamental interactions (strong, electromagnetic, weak, and gravitational) under even higher energy conditions.
Given the extremely high temperature of 1 × 10^17 K, we can infer that only the electroweak unification was in evidence at this time. Both the electromagnetic and weak interactions are unified under such extreme conditions.
Therefore, the mean photon energy at this instant was approximately 8.6173 × 10^12 eV, and the electroweak unification was in evidence.