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Licemer1 [7]
3 years ago
8

Find the least frequency of incident light that will knock electrons out of the surface of a metal with a work function of 3eV.​

Physics
1 answer:
mixer [17]3 years ago
3 0

Answer:

The frequency must be: 725\,\,10^{12} \,Hz

Explanation:

If the work function of the metal (\phi) is 3 eV, then we can use the formula for the kinetic energy of an ejected electron:

KE= h*f-\phi

considering for the minimum KE = 0, and using the Plank constant h in eV s as: 4.14 * 10 ^(-15) eV s, to solve for the frequency:

h*f=\phi\\4.14*10^{-15} * f = 3\\f=3*10^{15}  /4.14\,\,\frac{1}{s} \\f=725\,10^{12} \,Hz

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Answer only number 6
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Answer:

<em>Answer A. Fission, steam, turbine, electricity, cool water</em>

Explanation:

<u>Nuclear Energy Production </u>

Nuclear energy is produced by splitting uranium atoms in a process called fission. This generates heat and it's managed to produce steam, which later is used by a turbine generator to generate electricity. The heat must be taken out of the system, so a cooling process, usually involving water is the final step.

Because nuclear power plants don't burn fuel, they are known as clean energy sources.

Answer A. Fission, steam, turbine, electricity, cool water

6 0
3 years ago
After Pedro had breakfast, he went for a run. Identify at least three energy transformations that had to take place to allow Ped
FinnZ [79.3K]

Answer:

1) Chemical to mechanical (calories -> muscle contractions)

2) mechanical to mechanical (muscle -> motion)

3) mechanical to thermal (motion -> heat from the body causes sweating)

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Explanation:

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3 years ago
A revolutionary war cannon, with a mass of 2090 kg, fires a 16.7 kg ball horizontally. The cannonball has a speed of 113 m/s aft
OLEGan [10]

Answer:

0.90291 m/s

0.45055 m/s

Explanation:

m_1 = Mass of canon = 2090 kg

m_2 = Mass of ball = 16.7 kg

v_1 = Velocity of canon

v_2 = Velocity of ball = 113 m/s

In this system the momentum is conserved

m_1v_1=m_2v_2\\\Rightarrow v_1=\dfrac{16.7\times 113}{2090}\\\Rightarrow v_1=0.90291\ m/s

The velocity of the cannon is 0.90291 m/s

Applying energy conservation

\dfrac{1}{2}m_1v_1^2+\dfrac{1}{2}m_2v_2^2=\dfrac{1}{2}m_2v^2\\\Rightarrow m_1v_1^2+m_2v_2^2=m_2v^2\\\Rightarrow v_2=\sqrt{\dfrac{m_1v_1^2+m_2v_2^2}{m_2}}\\\Rightarrow v_2=\sqrt{\dfrac{2090\times 0.90291^2+16.7\times 113^2}{16.7}}\\\Rightarrow v_2=113.45055\ m/s

The ball would travel 113.45055-113 = 0.45055 m/s faster

6 0
4 years ago
How many species go extinct every day??
Law Incorporation [45]
Approximately 150-200 species.
5 0
3 years ago
10 points
SOVA2 [1]

Explanation:

u=0 m/s

v=9.6 m/s

s= 40.5 m

a=?

V^2=u^2 +2as

9.6^2=0+2×a×40.5

92.16=81a

a=92.16/81

a=1.14m/s^2

3 0
3 years ago
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