Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 38: Q19P (page 1182)

(a) If the work function for a certain metal is 1.8 eV, what is the stopping potential for electrons ejected from the metal when light of wavelength 400 nm shines on the metal? (b) What is the maximum speed of the ejected electrons?

Short Answer

Expert verified
  1. The stopping potential is 1.3 eV.
  2. The maximum speed of the ejected electrons is 676 km/s.

Step by step solution

01

The expression of stopping voltage.

The expression of stopping voltage is given by,

Vstop=hef-Φe

Vstop=hcλe-Φe

….. (1)

Here, h is Planck’s constant, λis wavelength, e is charge of electron, ϕ is work function, and c is the speed of light.

02

(a) Determine the stopping potential for electrons:

Therefore, the stopping potential is 1.3 V.

03

(b) Determine the maximum speed of the ejected electrons:

It is known that,

Kmax=12mvmax2

and

Kmax=Ve

Therefore, by comparing both the above equation of kinetic energy, you get

Ve=12mvmax2vmax=2Vem

Hence, the maximum speed of the ejected electrons is 676 km/s.

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.

Start your free trial

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

For the thermal radiation from an ideal blackbody radiator with a surface temperature of 2000 K, let Icrepresent the intensity per unit wavelength according to the classical expression for the spectral radiancy and Iprepresent the corresponding intensity per unit wavelength according to the Planck expression. What is the ratio Ic/Ipfor a wavelength of

(a) 400 nm (at the blue end of the visible spectrum) and

(b) 200 μm(in the far infrared)?

(c) Does the classical expression agree with the Planck expression in the shorter wavelength range or the longer wavelength range?

Question:Consider a potential energy barrier like that of Fig. 38-17but whose height Ubis and 6eVwhose thickness Lis 0.70nm. What is the energy of an incident electron whose transmissioncoefficient is 0.0010?

Monochromatic light (that is, light of a single wavelength) is to be absorbed by a sheet of photographic film and thus recorded on the film. Photon absorption will occur if the photon energy equals or exceeds 0.6eV, the smallest amount of energy needed to dissociate an AgBr molecule in the film. (a) What is the greatest wavelength of light that can be recorded by the film? (b) In what region of the electromagnetic spectrum is this wavelength located?

Question: In Eq. keep both terms, putting A=B=ψ. The

equation then describes the superposition of two matter waves of

equal amplitude, traveling in opposite directions. (Recall that this

is the condition for a standing wave.) (a) Show that |♆x,t|2 is

then given by |♆(x,t)|2=2ψ02[1+cos2kx]

(b) Plot this function, and demonstrate that it describes the square

of the amplitude of a standing matter wave. (c) Show that thenodes of this standing wave are located at x=(2n+1)(14λ),where n=0,1,2,3,…

and λ is the de Broglie wavelength of the particle. (d) Write a similar

expression for the most probable locations of the particle.

Question: The current of a beam of electrons, each with a speed of 900m/s, is 5.00A. At one point along its path, the beam encounters

a potential step of height -1.25μV.What is the current on the other side of the step boundary?
See all solutions

Recommended explanations on Physics Textbooks

Engineering Physics

Read Explanation

Famous Physicists

Read Explanation

Further Mechanics and Thermal Physics

Read Explanation

Quantum Physics

Read Explanation

Modern Physics

Read Explanation

Space Physics

Read Explanation
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