Answer:
The light radiated from the Sun's surface reaches Earth in about 8 minutes. However, the energy of this light was released by fusion in the Sun's core about several hundred thousand years ago.
Explanation:
Nucleosynthesis is the fusion of lighter elements into heavier elements. For the Sun the main mechanism of fusion is the proton - proton chain, in which two hydrogen atoms fuse into helium, in the course of the fusion photons are created.
When those photons start their travel from the core to the surface of the star, they will interact with different atoms in the whole way (the main free path).
More precisely, when a photon¹ is absorbed by an electron in an atom of a particular element, the electron will get to a higher state. When it comes back to the ground state, a photon will be emitted again.
The process described above is repeating multiple times for every photon until they reach the Sun surface.
The whole process can take about several hundred thousand of years.
Key term:
¹Photon: Particle that constitutes light.
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Density is a measure of mass per unit of volume.
Density is a measure of mass per volume.
The average density of an object equals its total mass divided by its total volume.
An object made from a comparatively dense material (such as iron) will have less volume than an object of equal mass made from some less dense substance (such as water).
Perhaps the highest density known is reached in neutron star matter.
The singularity at the centre of a black hole, according to general relativity, does not have any volume, so its density is undefined.
Answer:
A. Sound waves can travel through and reflect off rock layers.
Explanation:
Reflection seismology is a process of "seeing" below the ground using artificial sources to create sound waves or the process of learning about rock layers beneath the surface of Earth using sound waves.
Sources on land, uses vibration trucks to shake the ground very powerfully to produce sound waves.
Thus, the sound waves will travel through the earth and reflect off rock layers having different acoustic properties. In order to record this reflections, we make use of a small instrument called geophones.
Answer:
0.75 g/cm^3
Explanation:
The formula for density:
Where m is the mass and V is the volume.
So, we can substitute values for m and V:
Therefore, the density is 0.75 g/cm^3 (watch the units!)