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In this I want to explain the photoelectric effect and the value of Planck’s constant H.
Planck’s constant is set up with a digital nano emitter photocell with a built-in digital regulated power supply and housing and is suitable for fixing on an optical bench. There are provisions to fix mercury vapor lamps with wooden housings on benches and to choke for mercury lamp optical filters, patch chords
Photo Electric Equation:
Hv ‘= 1/2 * mv ^ 2
h = plank constant
V ‘= frequency
m = mass of electron
v = velocity of electron
It is seen in such a way that if light is incident on some metals then electrons are emitted. These electrons are known as photoelectrons. The metal is known as photo metal. The emission of an electron by atoms of light is called the photoelectric effect.
Wide Electric Field:
1. The process of emission depends strongly on the frequency of radiation.
2. A critical frequency exists for each metal and only white light of high frequency can do so while low frequency is unable to excite radiation.
3. The emission of one electron is written at very short time intervals after the arrival of the radiations and the number of electrons is proportional to the intensity of the radiation.
The experimental facts given above are among the strongest evidence that electromagnetic fields are quantized and the quanta energy in the field is called E = hv ‘and their quanta photons.
Furthermore, it is assumed that electrons are bonded inside the metal surface with energy. It falls when the frequency of light is greater than the frequency of electrons.
Einstein explained the photo electric effect by quantum theory of light. If photon energy hv ‘light is incident on the photo metal then it is used in working to eject electron from orbit. In providing kinetic energy to electrons. The first part of the energy represented by a constant W0 is known as the work function. So we have
HV ‘= W0 + 1 / 2mV ^ 2
1. The minimum frequency is called the threshold frequency at which the photo energy hv ‘= W0. Photons below this frequency cause energy / electric fields.
2. The number of electrons emitted by the photo metal is directly proportional to the intensity because the intensity is directly related to the number of photons.
3. The kinetic energy of the photon electron is the motion directly to the frequency of incident radiation.
The minimum positive cathodic potential at a particular frequency to prevent a rapidly emitting electron is known as a potential stop. So the stopping potential is directly proportional to the frequency of the radiation emitted.
Photo metal as cathode and another electrode as an anode enclosed in a glass bulb is known as photo cell. Electrons are emitted by the action of light and at least by the anode to the photo metal. Thus a current known as the photo-current current in the circuit. If the bulb is filled with gas. The cell is known as the gas-filled type of vacuum, it is known as the vacuum type.
1. The experiment should be carried out in the dark room to prevent the photo cell from wandering.
2. The photo cell source of the light and filter must be perfectly aligned.
3. The photo cell should not come in contact with the direct light particle when the room is dimmed by observation.
4. Stopping capacity must be measured accurately.