Physics 2

which statement is NOT true about electrons?

electrons cannot move from one object to another by friction

The rough comparison of metric system charge -1.00 Coulomb to one electron’s charge is this:

one electron is a tiny fraction of -1.00 Coulomb

Charles Coulomb measured very small electrical forces with high precision using a torsion balance which

twists a set amount for each Newton of force

The first electron is the nearest neighbor to the target proton.  In what direction is the force of this nearest neighbor on the proton?

right

If the size of the nearest neighbor force on the proton is 200 nanoNewtons, then how large is the force from the second neighbor (2N) on the proton?

50nN

The unit of electric charge is called a

Coulomb

When you double the distance between the proton and electron, to 2 nanometers from 1 nanometer, the force of attraction is

Smaller, 0.0577 nN

If 1.51 x 10²⁰ electrons move through a pocket calculator during a full day’s operation, how many coulombs of charge moved through it?

-24.4

A certain lightning bolt moves +28.0 C of charge.  How many fundamental units of charge e is this?

1.75

The nearest neighbor interaction force is 279 nanoNewtons.

Calculate the size of the net force on the leftmost proton.

379.8

As you move positive charges further and further apart, their potential energy?

decreases

What is an electron-Volt?

the energy acquired by an electron across a potential difference of 1 volt

In a region of space, the electric potential decreases uniformly from east to west, and does not vary in any other direction. The electric field:

points west and is uniform

Which is the correct description of electrons and protons?

protons are positively charges, and electrons are negatively charged

For a Feynman diagram, where is time located?

vertical axis

What does the blue line represent in a Feynman diagram?

motion of electrons

Who determined protons were positive?

Ben Franklin

All of quantum field theory is based on?

Feynman diagram

what is the correct description of electrons and protons?

protons attract electrons and repel protons

V=kQ/r

electric potential V of a point charge

V for a point charge decreases with

distance

E for a point chrage decreases with

distance squared

What is the voltage 5.00 cm away from the center of a 1-cm diameter metal sphere that has a -3.00nC static charge?

-539 V

electric potential is

scalar

electric field

vector

additional voltages as numbers gives…

the voltage due to a combination of point charges

addition of individual fields as vectors gives

the total electric field

green lines represent

places where electric potential is constant

electric field lines point where?

radially away from the charge, and are perpendicular to equipotential lines

When is work zero?

force is perpendicular to motion

When is a conductor an equipotential surface?

in static situations

there can be no voltage difference across the surface of a conductor, or charges will flow

TRUE

an equipotential line

a line along which the electric potential is constant

what is a equipotential surface?

a 3D version of equipotential lines

process by which conductor can be fixed at zero volts by connecting it to the earth with a good conductor

grounding

1 N/C equals

1 V/m

voltage points btwn A nd B

Vab= Ed

E=Vab/d

general relationship btwn voltage and electric field is

E= -deltaV/delta s

magnitude of the force on a charge in an electric field is obtained from

F=qE

electric potential per unit charge

V=PE/q

1V=

1 J/C

C x V

J

most common energy unit for submicroscopic processes

electron volt

electrical potential energy will decrease radially inward

kinetic energy increases outward

proton electron (lines of force

electric potential energy will decrease radially outward

proton proton lines of force

arrows are outward, q>0

proton towards proton

arrows point inward q<0

proton towards electron

what is inversley proportional to distance btwn two objects squared?

force

separation of positive and negative charges in a neutral object

polarization

What allows transfer of charge to and from the earth’s large reservoir?

grounding

can objects be charged by contact with another charged object and obtain the same sign charge

yes

what happens if an object is temporarily grounded?

it can be charged by induction and obtain opposite sign charge

polar molecules

have an inherent separation of charge

What is induction?

process by whivh an electrically charged object brought near a neutral object creates a charge in the object

Is the coulomb force stronger compared to gravitational force?

yes

Which can cancel… gravitational or coulomb?

COULOMB

grvaitational force is just

attractive

coulomb force is

attractive or repulsive

How is the electric field defined?

it represents only the source charge and it is unique at every point in space

electric field

E= F/q

electric field depends on whate?

Q (charge) and r (distance)

electric field is independent of…?

test charge q

magnitude of electric field

E=k Q!/ r2