I think it’s B but I might be wrong
A guitarist is tuning a guitar. She hears a low beat every 2.0 seconds. What is the difference between the correct frequency and measured frequency of the guitar string?
A "beat" is an audible period that arises due to a difference wave between two sine oscillations. With that, if the guitarist hears 2 beats per second, i.e., at a frequency of 1/2s = 0.5 Hz, the difference between the guitar and the reference (a tuner tool) is 0.5Hz. This could be due to the guitar being 0.5Hz under the reference, or 0.5Hz above the reference.
Which of these is outside of the solar system? sun Saturn galaxy moon
Our solar system consists of the sun and the 9 planets and their moons.
The galaxy is outside our solar system.
I would assume Galaxy, everything else is in our solar system.
please help me my H.W please show work
18. When its outermost shell is completely full
Explanation: an atom is unlikely to react when its outermost orbital is completely full with electrons. The atoms of these kind of elements are called noble gas, and they are unlikely to react with other elements because they do not accept electrons from other atoms and they do not give their electrons to other atoms, since their outermost shell is already full. Examples of noble gases are helium, neon and argon.
19. Types of nuclear radiation from lowest to highest energy:
- Beta radiation: beta particles are fast-moving electrons or positrons emitted in beta decay of the nuclei, and their energy typically ranges from a few hundreds keV to a few MeV
- Alpha radiation: alpha particles are nuclei of helium emitted in alpha decays of the nuclei, and their energy is typically of 5 MeV
- Gamma radiation: these are gamma ray photons emitted from nuclei in excited state that decay back into the lowest energy state. Typical energy of gamma radiation are a few MeV.
20. The false statement is C
In fact, it's actually the opposite: fission and fusion are two processes that release huge amount of energy, according to Einstein's famous equation
[tex]E=\Delta mc^2[/tex]
where E is the energy released, [tex]\Delta m[/tex] the variation of mass between initial and final products, and c is the speed of light. Given the huge value of [tex]c^2[/tex], we see that even for a tiny mass difference the amount of energy released in these processes is very big.
21. Uranium-235 and uranium-238
Uranium-238 is the naturally occuring radioisotope used in the nuclear reactors. However, since it is not fissile, it is enriched with another isotope, the uranium-235, which is fissile and therefore can substain the chain reaction in the nuclear reactor.
22. Because it is written as first element
In the chemical formula of a ionic compound (such as [tex]MgO[/tex]), the first element is the cathion (positive ion) while the second one is the anion (negative ion). This means that the magnesium (Mg) is the element with one electron in excess (therefore, it is the metal, since metals are the element with free electrons), while oxygen (O) is the non-metal, since it actually has 1 vacancy in its outermost shell.
23. 19: atomic number, 39.098: atomic mass
There are two numbers that characterize an element:
- atomic number (indicated with Z): it is the number of protons in the nucleus --> for potassium, Z=19, since it contains 19 protons
- mass number (indicated with A): it is the number of protons+neutrons in the nucleus, and it is calculated as an average between the different isotopes of the element. In this case, A=39.098, which means that on average potassium contains 39.098 protons+neutrons
24: X and Z have similar properties
The chemical properties of an element are determined by the number of valence electrons that it has: in fact, this number determines how much the element tends to react with other elements.
Elements that have the same number of valence electrons, therefore, react with other elements in a similar way, so they also have similar properties.
What two factors keep Earth in orbit and around the sun and the moon in orbit around Earth?
A) force and speed
B) mass and distance
C) gravity and inertia
Eliminate
D) gravity and distance
The correct answer is C. Gravity and inertia.
Explanation
Gravity is a force that makes objects attract other objects. Earth, planets, sun, moon, and other objects in the universe have forces of gravity that allow them to be in a constant orbit. For example, the sun's gravity makes the planets of the solar system rotate around it, however, not only does the force of gravity act. The other factor that influences this movement is the law of inertia that establishes that an object is going to remain in constant rest or movement with constant speed as long as an external force does not act on it. Therefore, it is possible to affirm that what allows the Earth to orbit around the Sun and the moon around the Earth, is the force of gravity and the law of inertia. So, the correct answer is C. Gravity and inertia.