According to the experiments concerned with photoelectric effect, what would inrease the kinetic energy of electron ejected from a metal surface? Decreasing the wavelength of the light, drecreasing the frequency of the light or increasing the number of photons of light striking the surface? Please help me with this question, im trying to understand it but after reading so many different answers in wikipedia and any other online source i'm getting even more confused!
If you will go to the wikipedia site below and scroll down the page, you will come to two sections that clearly tell you that increasing the frequency (decreasing the wavelength) increases the K. E. of the electrons. Scroll to Experimental Results of Photoelectric Emission (item # 4) and the section directly following "Mathematical Description" in which the formula is Kmax = hf - work function.
Note that making f more will make Kmax more.
http://en.wikipedia.org/wiki/Photoelectric_effect
To understand how certain factors affect the kinetic energy of electrons ejected from a metal surface in the photoelectric effect, let's break down the key concepts involved.
The photoelectric effect refers to the emission of electrons from a metal surface when light (photons) is incident upon it. When a photon strikes the surface of a metal, it can transfer its energy to an electron, allowing it to be ejected.
The kinetic energy (KE) of an electron can be calculated using the equation:
KE = hν - φ,
where KE is the kinetic energy, h is Planck's constant (6.626 x 10^-34 J·s), ν is the frequency of the incident light, and φ is the work function of the metal (the minimum energy required to eject an electron).
Now, let's analyze the given options and their effects on the kinetic energy of the ejected electron:
1. Decreasing the wavelength of the light:
The wavelength (λ) and frequency (ν) of light are inversely proportional (c = λν, where c is the speed of light). When the wavelength decreases, the frequency increases, and vice versa.
As the frequency increases, the kinetic energy of the ejected electrons also increases, following the KE = hν - φ equation. Therefore, decreasing the wavelength (increasing the frequency) of the light increases the kinetic energy of the ejected electrons.
2. Decreasing the frequency of the light:
As stated above, frequency and kinetic energy are directly proportional. So, decreasing the frequency of the light would result in a decrease in the kinetic energy of the ejected electrons.
3. Increasing the number of photons of light striking the surface:
The number of photons striking the surface, known as the intensity of light, affects the number of electrons ejected but not their individual kinetic energy. Increasing the number of photons only increases the number of electrons being emitted (current), not their energy.
Summing up, decreasing the wavelength (or increasing the frequency) of the light increases the kinetic energy of the ejected electrons, while decreasing the frequency of the light decreases their kinetic energy. The number of photons striking the surface does not directly affect the energy of the ejected electrons.
Note: The work function φ of the metal also plays a role in determining the kinetic energy. If the energy of the incident photons (hν) is less than the work function, no electrons will be ejected regardless of the wavelength, frequency, or number of photons.