Chapter 29, Problem 18PE

### College Physics

1st Edition
Paul Peter Urone + 1 other
ISBN: 9781938168000

Chapter
Section

### College Physics

1st Edition
Paul Peter Urone + 1 other
ISBN: 9781938168000
Textbook Problem

# Unreasonable ResultsRed light having a wavelength of 700 nm is projected onto magnesium metal to which electrons are bound by 3.68 eV. (a) Use KE e = h f − BE to calculate the kinetic energy of the ejected electrons. (b) What is unreasonable about this result? (c) Which assumptions are unreasonable or inconsistent?

(a)

To determine

The kinetic energy of the ejected electrons.

Explanation

Given:

Wavelength of light =Î»=700Â nmÂ =Â 700Â Ã—Â 10âˆ’9Â m

Frequency of light =f

Binding energy of metal =BE=3.68Â eV

Binding energy =BE

Speed of light =c=3Â Ã—108Â msâˆ’1Â

Kinetic energy of ejected electrons =KE

Formula Used:

Frequency is given as,

â€ƒâ€ƒf=cÎ»

Energy of light is given as,

â€ƒâ€ƒE=hf

Kinetic energy of the ejected electrons is given as,

â€ƒâ€ƒKE=hfâˆ’BE

Calculation:

Frequency is given as,

â€ƒâ€ƒf=cÎ»

Inserting the values

â€ƒâ€ƒ

(b)

To determine

The factor that unreasonable about the result in part (a).

(c)

To determine

The assumption which is unreasonable or inconsistent.

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started