How do you find the work function of photoelectric effect?
You can see from the photoelectric equation that the condition f > f0 is necessary for the photoelectric effect to occur (because kinetic energy is positive). The quantity ϕ = h * f0 is called work function (expressed in units of energy) and it corresponds to the threshold frequency.
What is the formula of photoelectric effect?
The Formula for Photoelectric Effect Work function. The maximum possible kinetic energy of the emitted electron. It will be \frac{1}{2} mv^{2}, for mass m and velocity v of the electron.
How do you find Max ke?
Definition: The Maximum Kinetic Energy of a Photoelectron given Wavelength. The maximum kinetic energy of a photoelectron is given by ? = ℎ ? ? − ? , m a x where ℎ is the Planck constant, ? is the speed of light, ? is the wavelength of the incident photon, and ? is the work function of the metal surface.
How is Vstop calculated?
We can measure Vstop and calculate f for each of the given mercury wavelengths (c = f λ ). Equation 1 is in the form of a straight line, y = (slope)x + b. From the slope we can find Planck’s constant and from the intercept we can find the work function, and hence the binding energy of the electrons.
What is work function measured in?
Work function measurement techniques: The work function of a material can be measured with PES and Kelvin probe (KP). While PES allows the measurement of the absolute work function, KP only gives the contact potential difference (CPD) between the actual probe and the sample surface.
How do you determine the work function of a metal?
Their formula is W=−ϵF+Ws, where ϵF is the Fermi energy, a quantity determined by the density of electrons and the properties of the crystal lattice of the metal; you can work out reasonable approximations to this for alkali metals by using the free electron approximation.
What is is equal to MC Square?
E = mc2. It’s the world’s most famous equation, but what does it really mean? “Energy equals mass times the speed of light squared.” On the most basic level, the equation says that energy and mass (matter) are interchangeable; they are different forms of the same thing.
What is Hertz and Lenard’s observation?
Hertz and Lenards observation In 1887 by Heinrich Hertz observed that when light falls on a metal surface, some electrons near the surface absorb enough energy from the incident radiation to overcome the attraction of the positive ions in the material of the surface.