AskiitianExpert Shine
Last Activity: 15 Years ago
Hi
The electric field stores energy. The energy density of the electric field is given by
where
- is the permittivity of the medium in which the field exists
- is the electric field vector.
The total energy stored in the electric field in a given volume V is therefore
where
dV is the differential volume element
Energy associated with an electric field is 1/2ε0E2 . find the energy assosiated.
Then , apply the formula for photoelectric effect, i.e energy given = work fn + max K.E . Convert the respective units into ev.
Photoelectric effect
In effect quantitatively using Einstein's method, the following equivalent equations are used (valid for visible and ultraviolet radiation):
Energy of photon = Energy needed to remove an electron + Kinetic energy of the emitted electron
Algebraically:
where
- h is Planck's constant,
- f is the frequency of the incident photon,
- φ = hf0 is the work function (sometimes denoted W instead), the minimum energy required to remove a delocalised electron from the surface of any given metal,
- is the maximum kinetic energy of ejected electrons,
- f0 is the threshold frequency for the photoelectric effect to occur,
- m is the rest mass of the ejected electron, and
- vm is the speed of the ejected electron.