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
Elza [17]
3 years ago
12

In compliance with conservation of energy, Einstein explained that in the photoelectric effect, the energy of a photon (hv) abso

rbed by a metal is the sum of the work function (Φ), the minimum energy needed to dislodge an electron from the metal’s surface, and the kinetic energy (Ek) of the electron: hv = Φ + Ek. When light of wavelength 358.1 nm falls on the surface of potassium metal, the speed (u) of the dislodged electron is 6.40 x 10⁵ m7s. (a) What is Ek (½mu²) of the dislodged electron? (b) What is Φ (in J) of potassium?
Chemistry
1 answer:
3241004551 [841]3 years ago
7 0

Answer:

 a) 1.866 × 10 ⁻¹⁹ J      b)   3.685 × 10⁻¹⁹ J

Explanation:

the constants involved are

h ( Planck constant) = 6.626 × 10⁻³⁴ m² kg/s

Me of electron = 9.109 × 10 ⁻³¹ kg

speed of light = 3.0 × 10 ⁸ m/s

a) the Ek ( kinetic energy of the dislodged electron) = 0.5 mu²

Ek = 0.5 × 9.109 × 10⁻³¹ × ( 6.40 × 10⁵ )² = 1.866 × 10 ⁻¹⁹ J

b) Φ ( minimum energy needed to dislodge the electron ) can be calculated by this formula

hv =   Φ + Ek

where Ek = 1.866 × 10 ⁻¹⁹ J

v ( threshold frequency ) = c / λ where c is the speed of light and λ is the wavelength of light = 358.1 nm = 3.581 × 10⁻⁷ m

v = ( 3.0 × 10 ⁸ m/s ) / (3.581 × 10⁻⁷ m ) = 8.378 × 10¹⁴ s⁻¹

hv = 6.626 × 10⁻³⁴ m² kg/s ×  8.378 × 10¹⁴ s⁻¹ = 5.551 × 10⁻¹⁹ J

5.551 × 10⁻¹⁹ J = 1.866 × 10 ⁻¹⁹ J + Φ

Φ = 5.551 × 10⁻¹⁹ J - 1.866 × 10 ⁻¹⁹ J = 3.685 × 10⁻¹⁹ J

You might be interested in
An element belonging to the halogen family would be expected to have a ________ ionization energy and a ________ electron affini
nikklg [1K]
<span>An element belonging to the halogen family would be expected to have a large ionization energy and a large electron affinity.
Flourine, Chlorine, Bromine, Iodine and astatine are the elements that belongs to the halogen family and mostly they have high values of ionization energy. 
The amount of energy released when an electron is added to an atom or molecule to form a negative ion or anion is electron affinity.</span>Chlorine from this family has highest electron affinity.

8 0
3 years ago
What is anything that has mass and volume
Pavlova-9 [17]
Anything that has mass and volume (takes up space) is called matter.
3 0
3 years ago
Read 2 more answers
Which statement explains how the periodic table is arranged?. . A.. The periodic table is arranged by the radioactivity levels i
vova2212 [387]
The periodic table is arranged by the outermost electrons of the elements and this is the statement among the given statements that explains how the periodic table is arranged. The correct option among all the options that are given in the question is the second option or option "B".
7 0
3 years ago
Read 2 more answers
Citric acid (h3c6h5o7) is a product of the fermentation of sucrose (c12h22o11) in air. determine the mass of citric acid produce
Alex
2.50 x 2/1 = 5 mol of Citric Acid
5 x (3+72+5+112) = 960g of Citric Acid


Answer: 960g of Citric Acid

6 0
3 years ago
Read 2 more answers
The matter in this series of images is going through a change. Draw a conclusion about the type of change shown. Is it a physica
34kurt

Answer:

This is a chemical change because it has been lit on fire. When it is lit on fire, the fire has been made, heat has been made, and gasses produced from the fire have also been made. Because this introduces new matter to the pictures, it is a chemical reaction.

Explanation:

8 0
2 years ago
Other questions:
  • When must scientist conduct controlled experiments ?
    13·1 answer
  • If this reaction produced 19.6 g of kcl, how much o2 was produced (in grams)?
    10·1 answer
  • How many significant figures in 0.002030?
    15·2 answers
  • What is the actual yield if I reacted 100.0 g of uranium with excess bromine (uranium is the limiting reactant) and had an 83% y
    14·1 answer
  • 225 J of heat energy were absorbed when a 35.0 g sample of iron was warmed. What was the change in temperature?
    7·1 answer
  • 6. Which of the following could be a base in a water solution?
    7·1 answer
  • How is the behavior of food coloring in the cool and heated water different? What caused the differences in their behavior?
    12·2 answers
  • Which of the following statements is NOT
    10·1 answer
  • An oxidation-reduction reaction that is also a synthesis reaction
    9·1 answer
  • Why is the average atomic mass in the periodic table a decimal?
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!