In 1909, Millikan performed a famous experiment in which he measured the charge of the electron (and for which he won the Nobel prize). In his experiment, oil drops carrying excess electrons are made to float between two charged large parallel, horizontal plates, as shown, by adjusting a uniform vertical electric field between the plates so that the drops do not fall down. Suppose each drop has a mass of 3.3 x 10-15kg, and one of the drops floats (the net force on it is zero) when the electric field magnitude is 39,200 N/C. Charged plates Charged plates Drops (a) What is the net charge on this drop, and how many excess electrons does that correspond to? Note that the number of electrons is an integer, but due to experimental uncertainty, the number you initially calculate might not be an integer, so you will need to round! (b) How many electrons total are there in the drop (including all the electrons in the neutral atoms)? Assume that most of the weight of the oil is due to carbon atoms; Each carbon atom has 6 electrons. You will need to look up the atomic weight of carbon.

In 1909, Millikan performed a famous experiment in which he measured the charge of the electron (and for which he won the Nobel prize). In his experiment, oil drops carrying excess electrons are made to float between two charged large parallel, horizontal plates, as shown, by adjusting a uniform vertical electric field between the plates so that the drops do not fall down. Suppose each drop has a mass of 3.3 x 10-15kg, and one of the drops floats (the net force on it is zero) when the electric field magnitude is 39,200 N/C. Charged plates Charged plates Drops (a) What is the net charge on this drop, and how many excess electrons does that correspond to? Note that the number of electrons is an integer, but due to experimental uncertainty, the number you initially calculate might not be an integer, so you will need to round! (b) How many electrons total are there in the drop (including all the electrons in the neutral atoms)? Assume that most of the weight of the oil is due to carbon atoms; Each carbon atom has 6 electrons. You will need to look up the atomic weight of carbon.

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter19: Electric Forces And Electric Fields

Section: Chapter Questions

Problem 6P

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Similar questions

A circular ring of charge of radius b has a total charge q uniformly distributed around it. Find the magnitude of the electric field in the center of the ring. (a) 0 (b) keq/b2 (c) keq2/b2 (d) keq2/b (e) None of these answers is correct.
Two horizontal metal plates, each 10.0 cm square, are aligned 1.00 cm apart with one above the other. They are given equal-magnitude charges of opposite sign so that a uniform downward electric field of 2.00 103 N/C exists in the region between them. A particle of mass 2.00 1016 kg and with a positive charge of 1.00 106 C leaves the center of the bottom negative plate with an initial speed of 1.00 x 105 m/s at an angle of 37.0 above the horizontal. (a) Describe the trajectory of the particle, (b) Which plate does it strike? (c) Where does it strike, relative to its starting point?
A point charge of 4.00 nC is located at (0, 1.00) m. What is the x component of the electric field due to the point charge at (4.00, 2.00) m? (a) 1.15 N/C (b) 0.864 N/C (c) 1.44 N/C (d) 1.15 N/C (e) 0.864 N/C
Is it possible for a conducting sphere of radius 0.10 m to hold a charge of 4.0 C in air? The minimum field required to break down air and turn it into a conductor is 3.0 106 N/C.
Consider the electric dipole shown in Figure P19.20. Show that the electric field at a distant point on the + x axis is Ex 4 keqa/x3.
On a typical clear day, the atmospheric electric field points downward and has a magnitude of approximately 100 N/C. Compare the gravitational and electric forces on a small dust particle of mass 2.01015 g that carries a single electron charge. What is the acceleration (both magnitude and direction) of the dust particle?
The dome of a Van de Graaff generator receives a charge of 2.0 104 C. Find the strength of the electric field (a) inside the dome, (b) at the surface of the dome, assuming it has a radius of 1.0 m, and (c) 4.0 in front the center of the dome. Hint: See Section 15.5 to review properties of conductors in electrostatic equilibrium. Also, note that the points on the surface are outside a spherically symmetric charge distribution; the total charge may be considered to be located at the center of the sphere.
A particle with charge q on the negative x axis and a second particle with charge 2q on the positive x axis are each a distance d from the origin. Where should a third particle with charge 3q be placed so that the magnitude of the electric field at the origin is zero?
An electron and a proton, each starting from rest, are accelerated by the same uniform electric field of 200 N/C. Determine the distance and time for each particle to acquire a kinetic energy of 3.21016 J.
Give a plausible argument as to why the electric field outside an infinite charged sheet is constant.
Calculate the angular velocity of an electron orbiting a proton in the hydrogen atom, given the radius of the orbit is 0.5301010 m. You may assume that the proton is stationary and the centripetal force is supplied by Coulomb attraction.
A proton is fired from very far away directly at a fixed particle with charge q = 1.28 1018 C. If the initial speed of the proton is 2.4 105 m/s, what is its distance of closest approach to the fixed particle? The mass of a proton is 1.67 1027 kg.