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Dimas [21]
3 years ago
15

A laser beam of total power 1 mW and wavelength 365 nm is incident on a clean piece of metal in vacuum. The metal has a work fun

ction of 3.0 eV. Find the maximum possible number of photoelectrons that could be emitted from this metal per second, and the maximum possible kinetic energy of the emitted electrons in eV. How do your answers change if the laser wavelength is doubled to 730 nm?
Physics
1 answer:
Naily [24]3 years ago
7 0

Answer: 1.84* 10 ^15 electrones /s for 365 nm. Maximum energy kinetic, 0.4 eV.

0 electrons/s for 730 nm,

Explanation: In order to solve this problem we have to take into account the following relationship for the the power is laser beam.

Power= Energy/time so we can considerer a numeber electrons/time* energy of each photon the we have the power of photon flux given by:

P=n*hν where n is the number of electrons per second and h the Plack constant.

The phton energy is equal h*c/λ;  where c is the speed of light

for  λ = 365 nm  we have E=1240/365 nm=3.4 eV ( 1eV=1.6 * 10^-19J)

so n= P/hν=1*10^-3/3.40 *1.6*10^-19 =1.84 * 10^15 electrons/s

The maximun kinetic energy of photolectrons is given by:

hν-W= Ek where W is the work function

then Ek=(3.4-3)eV= 0.4 eV

Finally, for the case of  λ =730 nm, the energy for this photon is

E=1240/730=1.7 eV

so with this energy it is not possible to obtain any photoelectrons because this energy is lower that the work fuction for this material.

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Source localization in ocean acoustics is posed as a machine learning problem in which data-driven methods learn source ranges d
Temka [501]

Source localization in ocean acoustics is posed as a machine learning problem in which data-driven methods learn source ranges directly from observed acoustic data: True.

<h3>What is machine learning?</h3>

Machine learning (ML) is also known as artificial intelligence (AI) and it can be defined as a subfield in computer science which typically focuses on the use of computer algorithms, data-driven techniques (methods) and technologies to develop a smart computer-controlled robot that has the ability to automatically perform and manage tasks that are exclusively meant for humans or solved by using human intelligence.

In Machine learning (ML), data-driven techniques (methods) are used to learn source ranges directly from observed acoustic data in a bid to proffer solutions to source localization in ocean acoustics.

In conclusion, a normalized sample covariance matrix (SCM) is constructed and used as the input, especially after pre-processing the pressure that's received by a vertical linear array in Machine learning (ML).

Read more on machine learning here: brainly.com/question/25523571

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6 0
2 years ago
How much force is needed to stretch a spring 1. 2 m if the spring constant is 8. 5 N/m? 7. 1 N 7. 3 N 9. 7 N 10. 2 N.
statuscvo [17]

The amount of force required to stretch or compress the spring is known as the spring force. Its unit is Newton(N). Force is needed to stretch spring is 10.2 N.

<h3>What is spring force?</h3>

The force required to extend or compress a spring by some distance scales linearly with respect to that distance is known as the spring force. Its formula is

F = kx

The given data in the problem is;

F is the spring force =?

K is the spring constant= 8.5 N/m

x is the length by which spring got stretched = 1.2m

\rm F_S=Kx \\\\ \rm F_S=8.5 \times 1.2 \\\\ \rm F_S=10.2 N

Hence the force is needed to stretch the spring is 10.2 N.

To learn more about the spring force refer to the link;

brainly.com/question/4291098

6 0
2 years ago
A submarine is 2.84 102 m horizontally from shore and 1.00 102 m beneath the surface of the water. A laser beam is sent from the
xxMikexx [17]

Answer:

468 m

Explanation:

So the building and the point where the laser hit the water surface make a right triangle. Let's call this triangle ABC where A is at the base of the building, B is at the top of the building, and C is where the laser hits the water surface. Similarly, the submarine, the projected submarine on the surface and the point where the laser hit the surface makes a another right triangle CDE. Let D be the submarine and E is the other point.

The length CE is length AE - length AC = 284 - 234 = 50 m

We can calculate the angle ECD:

tan(\hat{ECD}) = \frac{ED}{EC} = \frac{100}{50} = 2

\hat{ECD} = tan^{-1} 2 = 63.43^o

This is also the angle ACB, so we can find the length AB:

tan(\hat{ACB}) = \frac{AB}{AC} = \frac{AB}{234}

2 = \frac{AB}{234}

AB = 2*234 = 468 m

So the height of the building is 468m

5 0
3 years ago
Search about non-ohmic devices in 3 pages​
Tomtit [17]

Answer:

electronic diode,

Explanation:

Non-ohmic conductors are materials that do not obey ohm's law and they are electronic diode, transistors, tungsten, thermistors and vacuum tube etc.

7 0
3 years ago
A light wave encounters a partial physical barrier, such as a wall with a hole in it. What is MOST LIKELY to occur?
tatiyna
Most likely, the light wave will be absorbed by the wall. Without any information as to the size and color of the wall, the location and size of the hole, or the location of the light wave, this is a generalized probability problem. For all of the places the light could be, it's more likely that it hits the wall than the hole (if the hole is less than 50% of the area of the wall).
5 0
3 years ago
Read 2 more answers
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