How is Millikan oil drop experiment calculated?
When the charged drops fell at a constant rate, the gravitational and electric forces on it were equal. Therefore, the charge on the oil drop was calculated using formula Q = [latex]\frac {m\cdot g}{E}[/latex] Millikan found that the charge of a single electron was 1.6 x 10-19 C.
What forces act on an oil droplet?
The different forces acting on a oil drop falling through air (left) and rising through air due to an applied electric field (right). The most obvious force is the gravitational pull of the Earth on the droplet, also known as the weight of the droplet. The droplet also experiences a drag force that opposes its motion.
Why oil is used in Millikan oil drop method?
The oil was of a type usually used in vacuum apparatus and was chosen because it had an extremely low vapour pressure. Ordinary oil would evaporate under the heat of the light source causing the mass of the oil drop to change over the course of the experiment.
How many negative charges does the drop contain?
The drop contains 37 negative charges.
What are possible charges of oil droplets?
The tabulated data are examples of a few possible values. (CC BY 4.0; OpenStax). Looking at the charge data that Millikan gathered, you may have recognized that the charge of an oil droplet is always a multiple of a specific charge, 1.6×10−19C.
Which oil is used in Millikan oil drop method?
vacuum pump oil
Ernest Z. Millikan used vacuum pump oil for his experiment.
What are the possible charge of oil droplets?
Looking at the charge data that Millikan gathered, you may have recognized that the charge of an oil droplet is always a multiple of a specific charge, 1.6×10−19C.
How do you know the charge of an electron?
Since the value of the elementary charge is roughly 1.602 x 10-19 coulombs (C), then the charge of the electron is -1.602 x 10-19 C. When expressed in atomic units, the elementary charge takes the value of unity; i.e., e = 1. Thus, the electron’s charge can be denoted by -e.
Who did the oil drop experiment?
Robert Millikan’s
Robert Millikan’s famous oil drop experiment, reported in August 1913, elegantly measured the fundamental unit of electric charge.
What is the formula for Millikan’s oil drop experiment?
Millikan’s experiment was meant to have the drops fall at a constant rate. At this constant rate, the force of gravity on the drop and the force of the electric field on the drop are equal: F up = F down. [latex]\\cdot[/latex]F up = Q[latex]\\cdot[/latex]E F down = m[latex]\\cdot[/latex]
Why did Millikan use oil instead of water?
This brings us to the experiment you are doing. Professor Millikan has made several innovations to improve the experiment. First, droplets of oil are used instead of water, to reduce the tendency of the droplets to evaporate while the experiment is being performed.
How did Robert Millikan calculate the charge of an electron?
Therefore, the charge on the oil drop was calculated using formula Q = [latex]\\frac {m\\cdot g} {E} [/latex] Millikan found that the charge of a single electron was 1.6 x 10 -19 C. oil drop experimentExperiment performed by Robert Millikan and Harvey Fletcher in 1909 to measure the charge of the electron.
Why did Millikan win the Nobel Prize for Physics?
In 1923, Millikan won the Nobel Prize in physics in part because of this experiment. Aside from discerning an electron’s charge, the beauty of the oil drop experiment lies in its simple and elegant demonstration that charge is actually quantized.