Physics 112 Exam 1
either positively or negatively
A balloon will stick to a wooden wall if the balloon is charged
electrons than protons
A negative ion has more
attraction
A negatively charged rod is brought near a metal conductor. The protons in the metal conductor experience a force of
electrons
A negatively charged rod is brought near a metal conductor. Which, if any, particles move away from the rod?
no force at all
A positively charged rod is brought near a metal conductor. The neutrons in the metal conductor experience a force of
repulsion
A positively charged rod is brought near a metal conductor. The protons in the metal conductor experience a force of
none
A positively charged rod is brought near a metal conductor. Which, if any, particles move away from the rod?
2 Ohms
A resistor has 12 A of current flowing through it when directly connected to a 24 V power supply. What is its resistance value?
0.5 Ohms
A resistor has 24 A of current flowing through it when directly connected to a 12 V power supply. What is its resistance value?
1.5 Ohms
A resistor has 8 A of current flowing through it when directly connected to a 12 V power supply. What is its resistance value?
spread farther apart
An electroscope is charged negatively having by foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves
fall closer together
An electroscope is charged positively having foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves
spread farther apart
An electroscope is charged positively having foil leaves that stand apart. As a positive charge is brought close to the electroscope, the leaves
has fewer freely moving electrons
An insulator differs from a conductor in that an insulator
electrons in the knob move from the knob toward the leaves
As a negatively charged rod moves toward the knob of a neutral electroscope,
four times as large.
At half the distance from an isolated charge, the electric field strength will be ___________.
loosely bound
Charge carriers in a metal are electrons rather than protons because electrons are
away from a positive charge
Electric field lines always point...
Newtons/Coulomb
Electric field strength is expressed in what units?
electric field and gravitational field ?
Every proton in the universe is surrounded by its own
positively charged
Holding the knob of a Leyden jar and touching the outer metal with a negatively charged rubber rod will make the inside of the Leyden jar
positively charged
Holding the knob of a Leyden jar and touching the outer metal with a positively charged glass rod will make the outside of the Leyden jar
2.7 kW*hr
How many kiloWatt*hours of electrical energy are consumed by a 30 W electrical appliance that is used 3 hours each day of a 30 day month?
18 kW*hr
How many kiloWatt*hours of electrical energy are consumed by a 300 W electrical appliance that is used 2 hours each day of a 30 day month?
47 protons, 62 neutrons, 49 electrons
How many protons, neutrons, and electrons are in a single atom of Ag-109 if it has a -2 charge?
28 protons, 32 neutrons, 26 electrons
How many protons, neutrons, and electrons are in a single atom of Ni-60 if it has a +2 charge?
47 protons, 60 neutrons, 47 electrons
How many protons, neutrons, and electrons are in a single neutral atom of Ag-107?
0.5 Amps
How much current flows through a 20.0 Ohm resistor when connected to a 10.0 V power supply?
24.2 mA
How much current flows through a 330 Ohm resistor when connected to an 8.0 V power supply?
324,000 J
How much energy is consumed by a 30 W electrical device that is run for 3 hours?
also be attracted to
If a slow stream of water is attracted to a rubber rod, the slow stream of water will ____________________ a positive rod.
cut in half
If the cross-sectional area of a wire is doubled, its resistance will be ...
cut in half
If the length of a wire is cut in half, its resistance will be ...
doubled
If the length of a wire is doubled, its resistance will be ...
electroscope, Leyden jar, electrophorus
List these devices in the chronological order (oldest to newest) in which they were invented.
false
Regardless of the magnitudes of the charges, there will be a point between isolated positive and negative charges in which the magnitude of the electric field is zero.
true
Regardless of the magnitudes of the charges, there will be a point between two isolated positive charges in which the magnitude of the electric field is zero.
Ohm*cm
Resistivity is typically measured in units of ...
negatively charged
Rub a balloon with fur and the balloon becomes
negatively charged
Rub a glass rod with silk and the silk becomes
negatively charged
Rub your hair with a comb and the comb becomes
positive ion
Strip electrons from an atom and the atom becomes a
90.0 N
Suppose the electrostatic force between two point charges 30 cm apart is 10.0 N. What is the resulting force if they are moved to 10 cm apart?
250 N
Suppose the force between two point charges separated by a distance d is 1000 N. What is the resulting force if both charges are cut in half?
1000 N
Suppose the force between two point charges separated by a distance d is 1000 N. What is the resulting force if both charges are doubled and then moved to twice as far apart?
500 N
Suppose the force between two point charges separated by a distance d is 1000 N. What is the resulting force if one charge is doubled and then moved to twice as far apart?
1000 N
Suppose the force between two point charges separated by a distance d is 1000 N. What is the resulting force if one charge is reduced to one-fourth of its initial value and then they are moved to half as far apart?
4000 N
Suppose the force between two point charges separated by a distance d is 1000 N. What is the resulting force if the charges are moved to half as far apart?
protons
The atomic number of an element gives the number of ____________ in a single atom of that element.
one-fourth as much ?
The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is
the product of their charges ?
The electrostatic force between two charged particles is directly proportional to _____________.
inversely/directly
The resistance of a piece of wire is _______________ proportional to its cross-sectional area and _______________ proportional to its length.
6 wet cells connected in series
This 12-Volt car battery is comprised of _________.
6 dry cells connected in series
This 9-Volt transistor battery is comprised of _________.
touch the knob of the electroscope with a positive rod
To charge an electroscope positively by conduction, you
ground the electroscope while bringing a negative rod near
To charge an electroscope positively by induction, you
series
To determine the current flowing through a resistor, an ammeter must be connected in ___________ with the resistor.
each coulomb of charge gains 100 joules of electric potential energy
To say that an electrical battery has an electric potential difference of 100 Volts means that
each coulomb of charge gains 100 joules of electric potential energy.
To say that an electrical battery has an electric potential difference of 100 Volts means that
each coulomb of charge gains 200 joules of electric potential energy
To say that an electrical battery has an electric potential difference of 200 Volts means that
100 joules of electric potential energy are transferred each second
To say that an electrical device has 100 Watts of power means that
200 coulombs of charge enter and leave the device every second
To say that an electrical device has a current of 200 Amps flowing through it means that
it would take 100 volts to cause 1 amp of current through the device
To say that an electrical device has a resistance of 100-ohms means that
its charges have been rearranged.
To say that an object is electrically polarized is to say
negatively charged
Touching the knob of a Leyden jar with a positively charged glass rod will make the outside of the Leyden jar
both balloons are charged with the same type of charge
Upon entering the room, you observe two balloons suspended from the ceiling. You notice that instead of hanging straight down vertically, the balloons seems to be repelling each other. You can conclusively say ...
90 Volts
What is the electric potential difference across a 30 Ohm resistor that has 3.0 Amps of current flowing through it?
42 Volts
What is the electric potential difference across a 300 Ohm resistor that has 140 mA of current flowing through it?
the same as the rod
When a charged rod is used to charge an electroscope by conduction, the electroscope obtains a charge that is
neither
When mylar and paper come into contact, which material gives protons to the other?
nylon
When nylon and amber come into contact, which material gives electrons to the other?
amber
When nylon and amber come into contact, which material takes electrons from the other?
both a and b
When two cells are connected in parallel, they are connected
positive to negative.
When two cells are connected in series, they are connected
copper - cardboard - steel - copper - cardboard - steel - copper - cardboard - steel
Which of the following would be a proper way to stack a Voltaic pile using copper and steel as the conducting metals and cardboard soaked in salt water as the electrolyte?
copper - cardboard - zinc - copper - cardboard - zinc - copper - cardboard - zinc
Which of the following would be a proper way to stack a Voltaic pile using copper and zinc as the conducting metals and cardboard soaked in salt water as the electrolyte?
copper and zinc
Which of these combinations of metals will produce the greatest electric potential difference in a fruit or vegetable cell?
von Kleist and Musschenbroek
Which scientist(s) invented the Leyden jar?
Johannes Wilke
Which scientist(s) invented the electrophorus?
electrons to move into the inner metal AND electrons to move out of the outer metal
While holding the outer metal of a Leyden jar with your hand, you touch the inner metal with a negatively charged rod. This action causes...
electrons to move out of the inner metal AND electrons to move into the outer metal
While holding the outer metal of a Leyden jar with your hand, you touch the inner metal with a positively charged rod. This action causes...
Electrons move from your finger into the electroscope
You charge an electroscope by touching it with a positively charged rod. What happens if you then touch the knob of the electroscope with your finger?
gives electrons to your finger
You construct a simple electrophorus out of a foam insulation board, an aluminum pie pan, and a styrofoam cup. When you charge the foam board by rubbing it with rabbit fur, set the pie pan on the board, and ground the pan with your finger, the pie pan
positively charged
You construct a simple electrophorus out of a foam insulation board, an aluminum pie pan, and a styrofoam cup. When you charge the foam board by rubbing it with rabbit fur, set the pie pan on the board, and ground the pan with your finger, the pie pan becomes
negatively charged
You construct a simple electrophorus out of a foam insulation board, an aluminum pie pan, and a styrofoam cup. When you charge the foam board by rubbing it with rabbit fur, the foam board becomes
gives electrons to your finger
You construct a simple electrophorus out of a glass plate, an aluminum pie pan, and a styrofoam cup. You charge the glass plate by rubbing it with silk, set the pie pan on the plate, ground the pan with your finger, and then lift the pan off the glass plate. You then touch the pan with your finger and the pan
neutral
You construct a simple electrophorus out of a glass plate, an aluminum pie pan, and a styrofoam cup. You charge the glass plate by rubbing it with silk, set the pie pan on the plate, ground the pan with your finger, and then lift the pan off the glass plate. You then touch the pan with your finger and the pan becomes
give each sphere -10 C of charge
You have -20 C of charge that you wish to divide among two identical spheres. How could you divide the charge between the spheres such that their repulsive force will be maximized?