1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Angelina_Jolie [31]
3 years ago
9

Photoelectric effect:

Physics
1 answer:
Lynna [10]3 years ago
5 0

Answer:

A. K = 0.546 eV

B. cooper and iron will not emit electrons

Explanation:

A. This is a problem about photoelectric effect. Then you have the following equation:

K=h\nu-\Phi=h\frac{c}{\lambda} -\Phi   (1)

K: kinetic energy of the ejected electron

Ф: Work function of the metal = 2.48eV

h: Planck constant = 4.136*10^{-15} eV.s

λ: wavelength of light = 410nm - 750nm

c: speed of light = 3*10^8 m/s

As you can see in the equation (1), higher the wavelength, lower the kinetic energy. Then, the maximum kinetic energy is obtained with the lower wavelength (410nm). Thus, you replace the values of all variables :

K=(4.136*10^{-15}eV)\frac{3*10^8m/s}{410*10^{-9}m}-2.48eV\\\\K=0.546eV

B. First you calculate the energy of the photon with wavelengths of 410nm and 750nm

E_1=(4.136*10^{-15}eV)\frac{3*10^{8}m/s}{410*10^{-9}m}=3.02eV\\\\E_2=(4.13610^{-15}eV)\frac{3*10^{8}m/s}{750*10^{-9}m}=1.6544eV

You compare the energies E1 and E2 with the work functions of the metals and you can conclude:

sodium = 2.3eV < E1

cesium = 2.1 eV < E1

cooper = 4.7eV > E1 (this metal will not emit electrons)

iron = 4.5eV > E1 (this metal will not emit electrons)

You might be interested in
Infrared and ultraviolet waves have different frequencies.
algol13

Answer:

For infrared and ultraviolet waves have different frequencies. Both types of wave can have harmful effects on human beings. Describe the harmful effects of infrared and ultraviolet waves, relating them to the frequencies of the waves. Medical studies indicate that prolonged IR exposure can lead to lens, cornea and retina damage, including cataracts, corneal ulcers and retinal burns, respectively. To help protect against long-term IR exposure, workers can wear products with IR filters or reflective coatings.When you look at the EM spectrum, UV waves are quite a bit smaller in wavelength than infrared, and x-rays/gamma rays are even smaller. Therefore, UV waves are probably causing more harm than infrared waves, and x-rays/gamma rays are probably doing even more damage.

                                              <u><em>Thank You</em></u>  

                                     Please mark me Brainliest

3 0
2 years ago
Which group of animals would be served best by the following adaptations?
aev [14]
The answer to this question would be: <span>A) animals that live in deserts 

</span>Desert temperature is high, especially in the day, <span>An animal that lives in the desert needs to adapt to the high temperature either by reducing the heat or by increasing heat loss. By becoming nocturnal, the animal also able to evade the sunlight so it was less exposed to the heat. 
Unlike other option, the desert is lacking water. Desert is mostly dry and water would be a resource that hard to find. In this case, k</span><span>idneys adapted to check water loss would be a great help</span>
5 0
3 years ago
Read 2 more answers
Select all the correct locations on the image.
Papessa [141]

Answer:

its the top 3 can confirm on plato

Explanation:

8 0
2 years ago
Read 2 more answers
La altura de un tornillo de banco respecto a la superficie es de 80 cm expresar dicha medida en pies..
Andrej [43]

Answer:

this measurement if feet is: 2.624672 ft

Explanation:

Notice that 80 cm can be expressed as 0.8 meters, and In order to convert from meters to feet, one needs to multiply the meter measurement times 3.28084. Therefore:

0.80 m can be written in feet as: 0.80 * 3.28084 feet = 2.624672 feet

3 0
3 years ago
A coffee filter of mass 1.5 grams dropped from a height of 3 m reaches the ground with a speed of 0.7 m/s. How much kinetic ener
Mademuasel [1]

The kinetic energy gained by the air molecules is 0.0437 J                

<h3 />

Given:

Mass of a coffee filter, m = 1.5 g

Height from which it is dropped, h = 3 m

Speed at ground, v = 0.7 m/s

Initially, the coffee filter has potential energy. It is given by :

P =mgh

P = 1.5 × 10⁻³ kg × 9.8 m/s² × 3m

P = 0.0441 J

Finally, it will have kinetic energy. It is given by :

E= \frac{1}{2} mv^{2}

E= \frac{1}{2}×1.4 × 10⁻³ × (0.7)²

E = 0.000343 J

The  kinetic energy Kair did the air molecules gain from the falling coffee filter is :

E = 0.000343 -  0.0441

  = 0.0437 J

So, the kinetic energy Kair did the air molecules gain from the falling coffee filter is 0.0437 J

Learn more about kinetic energy here:

brainly.com/question/8101588

#SPJ4

8 0
2 years ago
Other questions:
  • What are the four basic perceptual characteristics of sound?
    13·2 answers
  • . List five endothermic reactions that are going on around you.
    13·1 answer
  • What is the climate of northern Alaska?
    6·2 answers
  • As an object in motion becomes heavier, its kinetic energy _____. A. increases exponentially B. decreases exponentially C. incre
    13·2 answers
  • Sharks are most common near coral reefs, because there are more fish there to eat.
    13·2 answers
  • In the southern hemisphere the summer solstice occurs when the sun is
    5·1 answer
  • What happens if two small positively charged particles of equal force are placed close to each other?
    13·2 answers
  • A woman of mass 50 kg is swimming with a velocity of 1.6 m/s. If she stops stroking and glides to a stop in the water, what is t
    8·1 answer
  • A polar bear runs at a speed of 8.3 m/s, how far will it travel in 60 seconds?
    14·2 answers
  • What is the correct answer?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!