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ivolga24 [154]
3 years ago
9

Electron kinetic energies are often measured in units of electron-volts (1 eV 1.6 x 10-19 J), which is the kinetic energy of an

electron that is accelerated through a 1 volt potential. When an aluminum plate is irradiated with UV light of 253.5 nm wavelength the ejected electrons are observed to have an average kinetic energy of about 0.8 eV. Use these results to determine the electron binding energy (or "work function") o of aluminum (in eV units).
Physics
1 answer:
PolarNik [594]3 years ago
5 0

Answer:

4.1 eV

Explanation:

Kinetic energy, K = 0.8 eV = 0.8 x 1.6 x 10^-19 J = 1.28 x 10^-19 J

wavelength, λ = 253.5 nm = 253.5 x 10^-9 m

According to the Einstein energy equation

E = W_{o}+K

Where, E be the energy incident, Wo is the work function and K is the kinetic energy.

h = 6.634 x 10^-34 Js

c = 3 x 10^8 m/s

E=\frac{hc}{\lambda }=\frac{6.634 \times 10^{-34} \times 3 \times 10^{8}}{253.5\times 10^{-9}}=7.85 \times 10^{-19} J

So, the work function, Wo = E - K

Wo = 7.85 x 10^-19 - 1.28 x 10^-19

Wo = 6.57 x 10^-19 J

Wo = 4.1 eV

Thus, the work function of the metal is 4.1 eV.

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Artemon [7]

Answer:

Explanation:

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μk=0.25

Since the body is moving in constant velocity, then the acceleration is zero(0).

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Fr=0.25×109.76

Fr=27.44N

Frictional force acting against the motion is 27.44N

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8 0
3 years ago
List 3 indicators that a chemical reaction has occurred.
mina [271]
Hello! There are many indicators to show a sign that a chemical reaction has occured. These are 3 as followed.

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3. A color change.

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8 0
3 years ago
Which of the angles shown in this picture is the angle of incidence?<br> A<br> B
Dmitry_Shevchenko [17]
The pictures are not attached, therefore, I cannot give a specific choice.
However, I will try to help you out.

The angle of incidence is defined as the angle formed between the ray of light and the normal to the surface that the ray is falling on.

The angle of incidence can be shown in the attached image.

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6 0
3 years ago
Read 2 more answers
Does Anybody Know The Answers?
ch4aika [34]

Answer:

I was going to give you the paper where I saw it but since you are not giving enough points I can not give you so I am only going to give you some of these that are here sorry

Explanation:

1.

9^{2} + 12^2 = x^2\\81 + 144= x^2\\\sqrt{225} = \sqrt{x} \\         15=x\\\\ 2.\\x^2+12^2+=13^2\\x^2+144 =169\\x^2 = 25\\\sqrt{x^2 =\sqrt{25\\\\

x=5

3.\\12^2+32^2 = x^2\\34.176= x

7.

5,12,13

9.

\frac{x}{4} ,\frac{12}{4} ,\frac{20}{4}\\\\\frac{x}{4},3,5  \\\\x=16\\\\12. \\x^2 + 48^2=50^2\\\\x^2=196\\x=14

Download docx
5 0
3 years ago
A student witnesses a flash of lightning and then t=2.5s later the student hears assiciated clap of thunder. (please show work)
frosja888 [35]

Answer:

857.5 m

2.8583×10⁻⁶ seconds

Explanation:

Time taken by the sound of the thunder to reach the student = 2.5 s

Speed of sound in air is 343 m/s

Speed of light is 3×10⁸ m/s

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⇒Distance travelled by the sound = 857.5 m

Time taken by light = Distance the light travelled / Speed of light

\text{Time taken by light}=\frac{857.5}{3\times 10^8}\\\Rightarrow  \text{Time taken by light}=2.8583\times 10^{-6}

Time taken by light = 2.8583×10⁻⁶ seconds

3 0
3 years ago
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