Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

The first three energy levels of the fictitious element X were shown in FIGURE P38.56. An electron with a speed of 1.4 X 106 m/s collides with an atom of element X. Shortly afterward, the atom emits a photon with a wavelength of 1240 nm. What was the electron's speed after the collision? Assume that, because the atom is much more massive than the electron, the recoil of the atom is negligible. Hint: The energy of the photon is not the energy transferred to the atom in the collision.

Short Answer

Expert verified

The electron's speed after collision is 6.14×105ms

Step by step solution

01

Given information

The first three energy levels of the fictitious element X were shown in FIGURE P38.56. An electron with a speed of 1.4 X 106 m/s collides with an atom of element X. Shortly afterward, the atom emits a photon with a wavelength of 1240 nm.

02

Explanation

First we determine the energy of the photon:

Eph=hcλ

Substitute the values:

Eph=6.63·10-34·3·1081240·10-9Eph=1eV

This energy corresponds 32 transition, so after collision atom is in the n = 3 state. Before collision atom was in ground state (n = 1).|

03

Calculations:

Energy which electron loses is:

ΔE13=E3-E1

Substitute the values:

ΔE13=-2(eV)+6.5(eV)ΔE13=4.5eV

ΔEk=ΔE13=4.5eV

The lost kinetic energy is given as:

-ΔEk=Ekf-Eki

Express in terms of Ekf

Ekf=Eki-ΔEk

The expression for kinetic energy is:

mvf22=mvi22-ΔEk

Express in terms of vf:

vf=2·mvi22-ΔEkm

Substitute the values:

vf=2·9.11·10-31·1.4·10622-4.5·1.6·10-199.11·10-31vf=6.14·105ms

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

What is the third-longest wavelength in the absorption spectrum of hydrogen?

A ruby laser emits an intense pulse of light that lasts a mere 10ns. The light has a wavelength of 690nm, and each pulse has an energy of 500mJ.

a. How many photons are emitted in each pulse?

b. What is the rate of photon emission, in photons per second, during the10ns that the laser is “on”?

a. Calculate the de Broglie wavelength of the electron in the n=1,2,and3states of the hydrogen atom. Use the information in Table 38.2 .

b. Show numerically that the circumference of the orbit for each of these stationary states is exactly equal to n de Broglie wavelengths.

c. Sketch the de Broglie standing wave for then=3 orbit

17. What is the de Broglie wavelength of a neutron that has fallen 1.0min a vacuum chamber, starting from rest?

The muon is a subatomic particle with the same charge as an electron but with a mass that is 207times greater: me=207mePhysicists think of muons as "heavy electrons," However, the muon is not a stable particle; it decays with a half-life of 1.5μsinto an electron plus two neutrinos. Muons from cosmic rays are sometimes "captured" by the nuclei of the atoms in a solid. A captured muon orbits this nucleus, like an electron, until it decays. Because the muon is often captured into an excited orbit ((n>1), its presence can be detected by observing the photons emitted in transitions such as 21and 31.

Consider a muon captured by a carbon nucleus (Z=6). Because of its long mass, the muon orbits well inside the electron cloud and is not affected by the electrons. Thus, the muon "sees" the full nuclear charge 2and acts like the electron in a hydrogen like ion.

a. What is the orbital radius and speed of a muon in the n=1ground state? Note that the mass of a muon differs from the mass of an electron.

b. What is the wavelength of the 21muon transition?

c. Is the photon emitted in the 21transition infrared, visible, ultraviolet, or xray?

d. How many orbits will the muon complete during 1.5μs? Is this a sufficiently large number that the Bohr model "makes sense, " even though the muon is not stable?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free