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3 years ago

Which statement best describes an atom?

Physics

2 answers:

Komok [63]3 years ago

6 0

<h3>Answer;</h3>

a group of protons and neutrons that are surrounded by electrons

<h3>Explanation;</h3>

An atom is the smallest particle of an element that can take part in a chemical reaction. Atoms of the same element are similar, while different elements have different atoms.
Atom of an element is made up of sub atomic particles, namely; protons, neutrons, and electrons. The nucleus of the atoms contains the protons and the neutrons, while the energy shells surrounding the nucleus contains the electrons.
The protons are positively charged , while the neutrons have no charge, which makes the nucleus positively charged. The electrons are negatively charged.

SpyIntel [72]3 years ago

5 0

The correct answer is going to be C, because in the nucleus of an atom there are protons and electrons; which can't move, and are surrounded by electrons on the electrical cloud

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kati45 [8]

Answer:

a current will be induced.

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3 years ago

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Which of the the following distance vs time graphs represents an object the is moving at constant non zero velocity

mario62 [17]

A graph with a horizontal line

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4 years ago

Which term means the distance between two bridge supports?

Ad libitum [116K]

The best answer is b - span.

A span is the distance between two bridge supports The supports may be towers, columns, or even the wall of a canyon.

There are many kinds of bridges but they all fall into three types namely beam, arch and suspension. The major difference between these three kinds of bridges is the distance that each can cross in a single span.

For example, a modern beam bridge is likely to span a distance of 200 feet, a modern arch can span 800 or 1000feet, and a modern suspension bridge can span up to 7000ft.

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3 years ago

An electron is projected with an initial speed vi = 4.60 × 105 m/s directly toward a very distant proton that is at rest. Becaus

frutty [35]

Answer:

$2.99\times 10^{-19}\ m$

Explanation:

Given:

$u$ = initial velocity of the electron = $4.60\times 10^5\ m/s$

$v$ = final velocity of the electron = $3u$

$x$ = initial position of the electron from the proton = very distant = $\infty$

Assume:

$m$ = mass of an electron = $9.1\times10^{-31}\ kg$

$e$ = magnitude of charge on an electron = $1.6\times10^{-19}\ C$

$p$ = magnitude of charge on an proton = $1.6\times10^{-19}\ C$

$k$ = Boltzmann constant = $9\times 10^9\ Nm^2/C^2$

$y$ = final position of the electron from the proton

$\Delta K$ = change in kinetic energy of the electron

$W$ = work done by the electrostatic force

$F$ = electrostatic force

$r$ = instantaneous distance of the electron from the proton

Let us first calculate the work done by the electrostatic force.

$W=\int Fdr\\\Rightarrow W = \int \dfrac{kep}{r^2}dr\\\Rightarrow W = kep\int \dfrac{1}{r^2}dr\\\Rightarrow W = kep\left | \dfrac{1}{r} \right |_{y}^{x}\\\Rightarrow W = kep\left ( \dfrac{1}{x}-\dfrac{1}{y} \right )\\\Rightarrow W = kep\left ( \dfrac{1}{x}-\dfrac{1}{\infty} \right )\\\Rightarrow W =\dfrac{kep}{x}$

Using the principle of the work-energy theorem,

As only the electrostatic force is assumed to act between the two charges, the kinetic energy change of the electron will be equal to the work done by the electrostatic force on the electron due to proton.

$\therefore \Delta K = W\\\Rightarrow \dfrac{1}{2}m(v^2-u^2)= \dfrac{kep}{x}\\\Rightarrow \dfrac{1}{2}m((3u)^2-u^2)= \dfrac{kep}{x}\\\Rightarrow \dfrac{1}{2}m(8u^2)= \dfrac{kep}{x}\\\Rightarrow x= \dfrac{2kep}{8mu^2}\\\Rightarrow x= \dfrac{2\times 9\times 10^9\times 1.6\times10^{-19}\times 1.6\times10^{-19}}{8\times 9.1\times10^{-31}\times (4.60\times 10^5)^2}\\\Rightarrow x=2.99\times 10^{-10}\ m\leq$

Hence, the electron is at a distance of $2.99\times 10^{-10}\ m$ when the electron instantaneously has speed of three times the initial speed.

8 0

4 years ago

What are 20 examples of energy transformation?

crimeas [40]

1. Chemical energy from food is converted to mechanical energy when the food is broken down and absorbed in the muscles.
2.The chemical energy from food can also be converted to thermal energy to keep the body warm.
3.When lightning strikes a tree, electrical energy is converted to thermal energy.
4.Chemical energy stored within batteries can be converted to electrical energy.
5.Electrical energy can be converted to light energy when a light is switched out.
6.Electrical energy can also be converted to sound energy when it is used to power a loudspeaker.
7.Sound energy is converted to electric energy in a microphone.
8.At hydroelectric water plants, gravitational potential energy is converted to electrical energy when water falls from a height.
9.Wind turbines convert the mechanical energy from the wind into electrical energy.
10.Solar panels convert light energy into electrical energy.
11.Electrical energy can be converted to mechanical and sound energy in a blender.
12.Chemical energy is converted to mechanical energy in cars when gasoline undergoes combustion to power the engine.
13.When fuels such as gasoline are combusted, chemical energy is converted to heat and light energy.
14.Nuclear energy is converted to heat and light energy in a nuclear reaction as seen in the sun and in atomic bombs.
15.Plants convert light energy to chemical energy through photosynthesis. 16.During bungee jumps, gravitational potential energy is converted to elastic potential energy.
17.Friction converts kinetic energy to thermal energy.
18.Waves convert mechanical energy to electrical energy.
19.Geothermal energy in geologically active regions of the world can be harnessed as electrical energy.
20.A ball dropped from a height is an example of a change of energy from potential to kinetic energy.

8 0

3 years ago