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If the work function of a metal is \(3.2 \mathrm{eV}\), what is the maximum wavelength that a photon can have to eject a photoelectron from this metal surface?

Short Answer

Expert verified
The maximum wavelength of a photon required to eject a photoelectron from the metal surface with a work function of \(3.2 eV\) is approximately \(391.4 nm\).

Step by step solution

01

Convert the work function to Joules

We need to convert the given work function from electron-volts (eV) to Joules (J). To do this, we'll use the conversion factor: \(1 \mathrm{eV} = 1.6 \times 10^{-19} \mathrm{J}\). Work Function (W) = \(3.2 \times 1.6 \times 10^{-19}\) J
02

Use the equation for work function

The work function equation is given by: \(W = h\frac{c}{\lambda}\), where: W = Work Function (in Joules) h = Planck's constant (\(6.63 \times 10^{-34}\) Js) c = speed of light in a vacuum (\(3.00 \times 10^{8}\) m/s) \(\lambda\) = maximum wavelength (in meters)
03

Solve for the maximum wavelength

Plugging in the values into the work function equation: \(3.2 \times 1.6 \times 10^{-19} = 6.63 \times 10^{-34} \times \frac{3.00 \times 10^{8}}{\lambda}\) Rearrange the equation to isolate \(\lambda\): \(\lambda = \frac{6.63 \times 10^{-34} \times 3.00 \times 10^{8}}{3.2 \times 1.6 \times 10^{-19}}\)
04

Calculate the maximum wavelength

Now, compute the maximum wavelength using the values: \(\lambda = \frac{6.63 \times 10^{-34} \times 3.00 \times 10^{8}}{3.2 \times 1.6 \times 10^{-19}} = 3.914 \times 10^{-7} \mathrm{m}\) The maximum wavelength of a photon required to eject a photoelectron from the metal surface is \(3.914 \times 10^{-7}\) meters or approximately 391.4 nm.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Work Function
The work function is a fundamental concept in the study of the photoelectric effect. It represents the minimum amount of energy that must be provided to an electron within a metal to overcome the attractive forces holding it within the material. This quantity is inherently linked to the type of metal and its electronic structure. The work function is usually expressed in electron volts (eV), a unit of energy specifically convenient when dealing with atomic-scale processes. When a photon with sufficient energy strikes the metal's surface, it can impart enough energy to an electron to escape the surface if that energy is greater than or equal to the metal’s work function. Understanding the work function is crucial because it sets the stage for the energy thresholds involved in the photoelectric process.

Planck's Constant
Planck's constant is a cornerstone of quantum mechanics. Designated by the symbol 'h', it represents the proportionality constant linking the energy of a photon to the frequency of its associated electromagnetic wave. The value of Planck's constant is approximately \(6.63 \times 10^{-34}\) Joule seconds (Js). This tiny number plays a key role in calculations across quantum physics, including the photoelectric effect. It's often encountered when examining phenomena at the atomic and subatomic levels, acting as a bridge between the observable world and the quantized nature of energy at microscopic scales. In the context of the photoelectric effect, Planck's constant is used to calculate the energy of incident photons and compare it against the work function to determine if electrons will be ejected from a material.

Wavelength of Photon
The wavelength of a photon relates to the color of light and is inversely proportional to its frequency and energy. In layman's terms, wavelength is the distance between two peaks of a wave of light. The significance of a photon’s wavelength comes into play when investigating light's interactions with matter, such as in the photoelectric effect. Photons with shorter wavelengths have higher energy, hence a higher capacity to liberate electrons from a metal's surface. If the wavelength is too long (and thus the energy too low), the photons won't have the requisite energy to eject electrons. The relationship between the wavelength of a photon and its ability to cause the photoelectric effect illuminates the particle-like behavior of light, one of the puzzling dual aspects of its nature. In the exercise provided, we calculate the maximum wavelength of a photon that can eject an electron based on the metal's work function.

Energy Conversions
Energy conversions in the context of the photoelectric effect revolve around the transformation of light energy into kinetic energy of electrons. When a photon with sufficient energy hits the metal's surface, its energy is used to overcome the work function, and any excess energy is converted into the kinetic energy of the ejected electron. This conversion from electromagnetic (light) energy to mechanical (motion) energy is a vivid example of energy's interchangeability. In analyzing these conversions, scientists can draw conclusions about the nature of light, the structure of matter, and the fundamental principles that dictate energy interactions. The exercise demonstrates how to use the work function and Planck’s constant to calculate the energy of a photon that can cause such a conversion, leading to the photoelectric effect.

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