Question

When light of wavelength, 115 nm, impinges a photocathode that has a binding energy of 2.59...

When light of wavelength, 115 nm, impinges a photocathode that has a binding energy of 2.59 eV, electrons are ejected. What is the speed (in m/s) of the ejected electrons? h = 6.626 x 10–34J·s, c = 2.9979 x 108m/s, 1 eV = 1.602 x 10–19 J, NA= 6.022 x 1023mol–1, me = 9.11 x 10–31 kg, KE = ½ mv2. Report your answer to three significant figures. It might be easier to enter your answer in scientific notation. So, for example, if your answer is 923672, in scientific notation and to 3 significant figures, the number is 9.24 x 105and you would enter 9.24e5.

Homework Answers

Answer #1

Given that

binding energy (or) work function W = 2.59 eV = 2.59 x 1.602 x 10–19 J = 4.15 x 10–19 J

Given that

wavelength λ = 115 nm = 115 x 10-9 m ( 1 nm = 10-9 m )

Energy E = hc / λ

h = planck's constant = 6.625 x 10-34 J.s

c = velocity of light = 3 x 108 m/s

Hence,

  E = hc / λ

=  (6.625 x 10-34 J.s) (3 x 108 m/s) / (115 x 10-9 m)

= 0.173 x 10-17 J

E =   0.173 x 10-17 J

We know that E = W + KE KE = kinetic energy

E = W + KE

KE = E - W =  0.173 x 10-17 J - 4.15 x 10–19 J = 0.1315 x 10-17 J

KE = (1/2) mv2 m = mass of electron, v = speed of electron

v = [ 2 KE/m ]1/2

      = [ 2 x 0.1315 x 10-17 J/ 9.11 x 10–31 kg ]1/2

     = 0.17 x 107 m/s

v = 0.17 x 107 m/s

Therefore,

speed of the ejected electrons = 0.17 x 107 m/s

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
1)A magnesium surface has a work function of 2.65 eV. Electromagnetic waves with a wavelength of...
1)A magnesium surface has a work function of 2.65 eV. Electromagnetic waves with a wavelength of 280 nm strike the surface and eject electrons. Find the maximum kinetic energy of the ejected electrons. Express your answer in electron volts. Ans in  eV 2)What is the energy of each of the two photons produced in an electron-positron annihilation? Use the following Joules-to-electron-Volts conversion 1eV = 1.602 × 10-19 J. The rest mass of an electron is 9.11×10^-31 kg. Ans in MeV
Calculate the energy in Joules for a photon with a wavelength of 400 nm. Report your...
Calculate the energy in Joules for a photon with a wavelength of 400 nm. Report your answer to 4 significant figures using scientific notation. (Ex: 1.345E-17 should be entered for 1.345 x 10-17)
Laser Wavelength Photoelectric Effect Observed? 300 nm Yes 525 nm No 325 nm Yes 425 nm...
Laser Wavelength Photoelectric Effect Observed? 300 nm Yes 525 nm No 325 nm Yes 425 nm No 600 nm No Table 2. Select Metals and Their Binding Energies Metal Electron Binding Energy (J) Cesium 3.124251e-19 Scandium 5.60763e-19 Silver 7.20981e-19 Rubidium 3.6209268e-19 1 .Which of the four elements listed is most likely to be the unknown metal? Rubidium Silver     Scandium Cesium 2.Calculate the kinetic energy of an electron ejected from the surface of a sample of Scandium when the metal is subjected...
When ultraviolet light with a wavelength of 400 nm falls on a certain metal surface, the...
When ultraviolet light with a wavelength of 400 nm falls on a certain metal surface, the maximum kinetic energy of the emitted photoelectrons is 1.10 eV . What is the maximum kinetic energy K0 of the photoelectrons when light of wavelength 330 nm falls on the same surface? Use h = 6.63×10?34J?s for Planck's constant and c = 3.00×108m/s for the speed of light and express your answer in electron volts.
When an x-ray photon with λλ 0 = 0.58 nm is incident on a target, it...
When an x-ray photon with λλ 0 = 0.58 nm is incident on a target, it undergoes Compton Scattering and is scattered at an angle of 26°. What is the wavelength λλ ' of the scattered photon (in nm)? (keep 7 significant figures in your answer) What is the energy (E) if the incident photon (in keV)? Use h = 4.136 x 10-15 eVs and c = 3 x 108 m/s. (keep 7 significant figures in your answer) What is...
A. What is the energy in 10-3 eV of a photon that has a momentum of...
A. What is the energy in 10-3 eV of a photon that has a momentum of 6.13×10−29 kg ⋅ m/s ? B. What is the energy in 10-9 eV of a photon in a radio wave from an AM station that has a 1,506 kHz broadcast frequency? C. Calculate the frequency in 1020 Hz of a 0.571 MeV γ-ray photon. D. A certain molecule oscillates with a frequency of 1.73×1013 Hz. What is the approximate value of n for a...
A laser emits light that has a frequency of 6.69 x 1014 s-1. If the laser...
A laser emits light that has a frequency of 6.69 x 1014 s-1. If the laser emits a “pulse” (a burst of light) that contains 7.0 x 1017 photons, what is the total energy of that pulse in Joules? Do not use scientific notation in your answer. Give the answer ( in Joules) to 2 significant figures.
Mass of a Moving Particle The mass m of a particle moving at a velocity v...
Mass of a Moving Particle The mass m of a particle moving at a velocity v is related to its rest mass m0 by the equation m = m0 1 − v2 c2 where c (2.98 ✕ 108 m/s) is the speed of light. Suppose an electron of rest mass 9.11 ✕ 10−31 kg is being accelerated in a particle accelerator. When its velocity is 2.84 ✕ 108 m/s and its acceleration is 2.49 ✕ 105 m/s2, how fast is...
If the atomic radius of a metal that has the simple cubic crystal structure is (4.20x10^-1)...
If the atomic radius of a metal that has the simple cubic crystal structure is (4.20x10^-1) nm, calculate the volume of its unit cell (in nm^3). Use scientific notation with 3 significant figures (X.YZ x 10^n). Note that Avenue automatically enters x10, so you only need to enter X.YZ and n. Note: Your answer is assumed to be reduced to the highest power possible.
1) Describe an example of each of the following that may be found of your kitchen:...
1) Describe an example of each of the following that may be found of your kitchen: Explain how your choice falls into this category, and if there is a chemical name or symbol for it, provide that as well. Provide a photo of your example with your ID card in it. a) a compound b) a heterogeneous mixture c) an element (symbol) Moving to the Caves… Lechuguilla Caves specifically. Check out this picture of crystals of gypsum left behind in...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT