Introduction To Health Physics
5th Edition
ISBN: 9780071835275
Author: Johnson, Thomas E. (thomas Edward), Cember, Herman.
Publisher: Mcgraw-hill Education,
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Chapter 2, Problem 2.8P
To determine
How many volts must be applied across the plates if the droplet is to remain suspended in the space between the plates if a 1-micron-diameter droplet of oil, whose specific gravity is 0.9, is introduced into an electric field between two large horizontal parallel plates that are 5-mm apart, across which there is a potential difference of V volts, if the oil droplet carries a net charge of 100 electrons?
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Students have asked these similar questions
In the Millikan oil-drop experiment illustrated in the figure below, an atomizer (a sprayer with a fine nozzle) is used to introduce many tiny droplets of oil between two oppositely charged parallel metal plates.
Some of the droplets pick up one or more excess electrons. The charge on the plates is adjusted so that the electric force on the excess electrons exactly balances the weight of the droplet. The idea is to look for
a droplet that has the smallest electric force and assume it has only one excess electron. Suppose we are using an electric field of 3.45 x 104 N/C. The charge on one electron is 1.60 x 10-19 C. Calculate the
radius of an oil drop of density 832 kg/m3 for which its weight could be balanced by the electric force of this field on one electron.
Oil droplets
Pinhole
Telescope with
scale in eyepiece
Light
um
The classic Millikan oil drop experiment setup is shown below.
In this experiment oil drops are suspended in a vertical electric field against the gravitational force to measure their charge. If the mass of a negatively charged drop suspended in an electric field of 1.76 ✕ 10−4 N/C strength is 8.620 ✕ 10−21 g, find the number of excess electrons in the drop.
The uniform electric field between two charged parallel plates
has a magnitude of 4400 V/m (note that 1 V/m = 1 N/C). If the
plates are separated by 0.0100 m and an electron is released
from the far negative side of the gap, what will the electron's
kinetic energy (in eV) and speed be when it just reaches the
positive plate? Note that the electron charge = -1.602 x 10-19 C
and the electron mass = 9.11 x 10-31 kg.
KE
V=
ev
m/s
Chapter 2 Solutions
Introduction To Health Physics
Ch. 2 - Two blocks of mass 0.1 kg and 0.2 kg approch each...Ch. 2 - A bullet whose mass is 50 g travels at a velocity...Ch. 2 - Compute the mass of the Earth, assuming it to be a...Ch. 2 - An automobile weighing 2000 kg and going at a...Ch. 2 - A small electrically charged sphere of mass 0.1 g...Ch. 2 - A capacitor has a capacitance of 10F . How much...Ch. 2 - A small charged particle whose mass is 0.01 g...Ch. 2 - Prob. 2.8PCh. 2 - Prob. 2.9PCh. 2 - Prob. 2.10P
Ch. 2 - Prob. 2.11PCh. 2 - Prob. 2.12PCh. 2 - Prob. 2.13PCh. 2 - Prob. 2.14PCh. 2 - Prob. 2.15PCh. 2 - A current of 25 mA flows through a 25-gauge wire,...Ch. 2 - An electron starts at rest on the negative plate...Ch. 2 - Prob. 2.18PCh. 2 - Prob. 2.19PCh. 2 - Prob. 2.20PCh. 2 - Prob. 2.21PCh. 2 - Prob. 2.22PCh. 2 - Prob. 2.23PCh. 2 - (a) A 1000-MW(e) nuclear power plant operates at a...Ch. 2 - Prob. 2.25PCh. 2 - Prob. 2.26PCh. 2 - Prob. 2.27PCh. 2 - The specific heat of water in the English system...Ch. 2 - Prob. 2.29PCh. 2 - Prob. 2.30PCh. 2 - Prob. 2.31PCh. 2 - Prob. 2.32PCh. 2 - How many cubic meters of water must fall over a...Ch. 2 - (a) Calculate the speed of a 25-MeV proton. (b)...Ch. 2 - Prob. 2.35PCh. 2 - Prob. 2.36PCh. 2 - Calculate the speed of a (a) 0.5-MeV electron and...Ch. 2 - How much sub-butuminous coal (20,000 kJ/kg) would...Ch. 2 - Prob. 2.40PCh. 2 - How much oil (138,690 Btu/gal) would it take to...Ch. 2 - How much oil (138,690 Btu/gal) would it take to...Ch. 2 - Prob. 2.43PCh. 2 - Prob. 2.44PCh. 2 - Prob. 2.45PCh. 2 - Prob. 2.46PCh. 2 - Prob. 2.47PCh. 2 - Prob. 2.48PCh. 2 - Prob. 2.49P
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