PHYSICS SMARTBOOK : ELECTROSTATIC FORCE
picture of an electroscope
A -> metal knob B -> insulator C -> metal foil leaves D -> enclosing flask
4.49 V
A battery delivers a 1.57-A current to a fluorescent light bulb. In 3.00 min it delivers 1.27 kJ of electrical energy. What potential difference does the battery create?
Blank 1: potential Blank 2: 12 Blank 3: J, Joules, or joules
A battery that creates a(n) ____ difference of 12 V does ____ _____ of work on each coulomb of charge.
Blank 1: electrons Blank 2: charged
A bolt of lightning is a narrow stream of _____ traveling at high speed along a conducting path created by ____ particles.
electroscope
A device that is used to detect electric charges and consists of a metal knob connected by a metal stem to two thin metal leaves is a(n) ____
electric current
A flow of charged particles is defined as a(n) ____
ampere
A flow of electric charge equal to one coulomb per second (1 C/s) is called a(n) ______ (A).
6.91 × 10^5 J
A heater has a resistance of 15.0 Ω and operates with a current of 8.00 A. How much thermal energy does the heater supply in 12.0 min?
4.2
A negative charge of -6.5 × 10-6 C exerts an attractive force of 83 N on a second object that has a charge of +2.5 × 10-6 C. The two charges are ____ cm apart
electric circuit
Any closed loop or conducting path allowing electric charges to flow is called a(n)
a conducting path from the ground to the cloud for the electrons.
As charge builds up in a cloud, molecules in the air break into positively and negatively charged particles. These particles can move freely in the air, establishing _____
Blank 1: magnitude Blank 2: direction
Because Coulomb's law is used to calculate a force, there must be ___ and ____ in the final reported value.
electrons or protons.
By definition, one coulomb is the magnitude of the charge on 6.24 × 1018 ____
charging a neutral object by touching it with a charged object.
Charging by conduction is the process of _____
charging a neutral object by bringing a charged object near it.
Charging by induction is the process of _____
1 battery 2 voltmeter 3 lamp 4 ammeter
Click and drag on elements in order Place the components in the circuit in the same order as the direction of conventional current flow, starting with the electron source. For parallel connections, put the meter component first.
Blank 1: force Blank 2: directly
Coulomb found that the ____ between two charged spheres varied ___ with the charges on the spheres.
Blank 1: inversely Blank 2: square
Coulomb found that the force on two charged spheres varied _____ with the _____ of the distance between the two spheres.
Blank 1: equal or identical Blank 2: equal or identical
Coulomb used spheres of _____ size in his apparatus to ensure that they received an _____ amount of charge.
the square of the distance between them.
Coulomb's law states that the force between two point charges varies directly with the product of their charge and inversely with _____
Blank 1: electrostatic Blank 2: proportional Blank 3: square
Coulomb's law summarizes observations showing that the ______ force between two charges is _______ to the product of the charges and inversely proportional to the ______ of the distance between them.
Blank 1: resistance Blank 2: conductors Blank 3: Ohm's
Different materials have different properties of _____, or resistivities. Metallic ______ generally obey _____ law, but many devices contain transistors and diodes, which do not obey it.
opposite to
During charging by induction, the charge that ends up on the object to be charged is always ______ the charge on the object used to induce the charge.
relation of energy and potential difference
E = qΔV
removing excess charge by touching an object to Earth.
Grounding is the process of ____
thousands of years
How long have people known about electrostatic forces?
definition of current
I = q/t
Blank 1: closed Blank 2: movement Blank 3: current
If a _____ path for the _____ of charged particles contains a charge pump, then a flow of charged particles, or an electric _____, is created.
Blank 1: attractive Blank 2: repulsive
In comparison to gravitational forces, which are always _____, electrostatic forces can be attractive or ____.
Blank 1: induction Blank 2: uniformly or evenly
In the process of spraying paint onto automobiles, the droplets of paint are charged by _____, causing them to repel each other and coat the surface _____.
- Moving water powers a waterwheel just as moving charges in an electric current power a motor. - A motor in an electric circuit and a waterwheel in a waterfall both depend on converting forms of potential energy into mechanical energy.
In which ways are electric current and water flow comparable?
Blank 1: current Blank 2: proportional Blank 3: difference
Ohm's law states that ____ through a material is directly _____ to the potential ____ between its ends.
definition of power
P = E/t
substitute for charge
P = IΔV
substitute for energy
P = qΔV/t
1 Make sure the two spheres are touching each other. 2 Bring a negatively charged rod close to one sphere. 3 electrons move from one sphere to the other one. 4 separate the two spheres. 5 the two spheres have equal and opposite charges.
Place the steps involved in charging two identical conducting spheres by induction in order from first to last.
battery
Several galvanic cells connected together are called a(n)
coulomb.
The SI standard unit of charge is the
Blank 1: potential Blank 2: potential Blank 3: kinetic
The charge pump in an electric circuit transforms mechanical or chemical energy to increase the electric ______ energy of the charges flowing in it. Devices in the circuit transform some of this electric ______ energy to forms of energy such as _____ energy in a motor or light energy in a lamp.
conventional current
The direction in which a positive test charge moves is the ____
magnitude of the charge of a single electron or proton.
The elementary charge is defined as the
you must know the charges on the objects experiencing the force.
The formula for Coulomb's law only allows for the magnitude of the force to be calculated. To find the direction of the force,
elementary charge
The magnitude of the charge of a single electron or proton is defined as the _____
resistance
The measure of how strongly an object or a material impedes current produced by a potential difference is
Blank 1: charging Blank 2: induction
The process of charging a neutral object by bringing a charged object near it is called _____ by ______.
Blank 1: charging Blank 2: conduction
The process of charging a neutral object by touching it with a charged object is called _____ by ______.
grounding
The process of removing excess charge by touching an object to Earth is called _____
Coulomb's law
The statement that the force between two point charges varies directly with the product of their charge and inversely with the square of the distance between them is known as
Blank 1: potential Blank 2: current Blank 3: constant Blank 4: resistance
The unit of resistance is named for Georg Ohm because he discovered that the ratio of ____ difference to ____ is ____ for a given conductor, so this ratio can be defined as the ____ of the conductor.
false
True or false: Given the current and resistance in a circuit, if you want to determine the thermal energy generated by the circuit in one minute, you must first find the power of the circuit.
1.4 × 10^3 N
Two objects, each having a +6.0 μC charge, are placed 1.5 cm apart. What is the magnitude of the force that each object will experience?
the direction in which a positive test charge moves
What is meant by conventional current?
the measure of how strongly an object or a material impedes current produced by a potential difference
What is resistance?
2.08 A
When a 25.0-V battery is connected to a 15.0-Ω resistor, what current flows in the circuit?
The electrons in the conductor move toward a positively charged object or away from a negatively charged object.
When a charged object is brought close to a neutral conductor, charges are forced to separate in the conductor. Which statement best explains what is occurring in this charge separation?
move apart, because they will have the same charge.
When a charged object touches the metal knob at the top of an electroscope, the leaves become charged by conduction. As a result, the leaves will ____
rotate away from the object.
When a negatively charged rod is suspended so that it turns easily, a negatively charged object brought near one end of the rod will cause the rod to ___.
Blank 1: separate Blank 2: positive Blank 3: negative
When a neutral conductor is brought close to a charged object, the charge on this object forces the charges in the neutral conductor to ___ because the electrons in the conductor move either toward the charged object if it is ____, or away from the charged object if it is ___.
Blank 1: charged Blank 2: transferred or exchanged Blank 3: conduction
When you touch a(n) ___ object to a neutral object, electrons are separated ___ between the objects so that the previously neutral object gains some charge. The previously neutral object has been charged by ___.
- paint applications for automobiles - toner particles in a laser printer
Which are examples of applications of electrostatic forces?
- Charged spheres are treated as if all of the charge is located at their centers. - The law is valid for charges that are uniformly spread over a sphere. - The law is valid for point charges.
Which considerations must be understood when using Coulomb's law?
electric current.
Which correctly completes the statement below? A flow of charged particles is a(n)
- dimmer switches - analog joysticks - control circuits for electric motors
Which devices make use of variable resistors?
R = ΔV/I
Which equation correctly relates current, potential difference, and resistance?
P = IΔV
Which equation correctly relates power, current, and potential difference?
- sensitivity of the metal leaves to small charges - enclosing the metal leaves to eliminate air currents - convenience of being able to check charge through conduction or induction
Which features are advantages of using an electroscope to detect charge?
any closed loop or conducting path allowing electric charges to flow
Which is the correct definition for an electric circuit?
Current through a material is directly proportional to the potential difference between its ends.
Which is the correct statement of Ohm's law?
ampere (A)
Which is the correct term for a flow of electric charge equal to one coulomb per second (1 C/s)?
battery
Which is the correct term for several galvanic cells connected together?
a device designed to have a specific resistance
Which is the definition of a resistor?
- potential energy - energy - charge
Which quantities are conserved in a complete electric circuit?
- The electrostatic force between two charges is inversely proportional to the square of their separation distance. - The electrostatic force between two charges is proportional to the product of the charges.
Which relationships form part of Coulomb's law?
Some electrical components obey Ohm's law, meaning they have constant resistance, at least over a certain range of voltages, but some do not.
Which statement accurately describes the resistances of electrical components?
The spherical shape would allow for the charge to be evenly distributed.
Which statement best describes why Coulomb used spheres in his apparatus?
F ∝ 1/d2
Which statement describes the proportionality between the force and the separation distance between two charged spheres?
F ∝ qAqB
Which statement describes the proportionality between the force between two charged objects and the quantity of charge on each object?
- Like charges repel, unlike charges attract. - There are two kinds of charge: positive and negative. - Electrostatic forces between charges grow stronger as the charges get closer together.
Which statements about charges are correct?
- Changing the potential difference changes the current proportionally. - Changing the resistance changes the current in inverse proportion.
Which statements about controlling the current in a circuit are accurate?
- The direction of conventional current is opposite to the direction of electron flow. - Any flow of charged particles is considered an electric current. - Electric current requires a potential difference.
Which statements about electric current are accurate?
ohm
Which unit is used for the quantity that is the ratio of potential difference to current?
Earth is so large that it can absorb or release large amounts of charge without becoming noticeably charged itself.
Why is it that Earth is able to neutralize a positively or a negatively charged object when the object is grounded?
When larger charges approach each other, the charges will separate and will no longer be uniform.
Why is it that larger charged spheres pose a problem when using Coulomb's law?
Blank 1: Grounding Blank 2: negatively Blank 3: positively
_____ is a process by which a charged object can become neutral through contacting Earth, either directly or through a conductor. The contact allows electrons to move away from the object, if it is _____ charged, or to move onto the object if it is ______ charged.
potential energy to kinetic energy
a waterwheel in a waterfall and an electric circuit containing an electric motor
kinetic energy to sound energy
a waterwheel in a waterfall but not an electric circuit containing an electric motor
F
ammeter
kinetic energy to potential energy
an electric circuit containing an electric motor but not a waterwheel in a waterfall
E
battery
battery
chemical energy to electric potential energy
I
current
refrigerator
electric potential energy to kinetic energy
heater
electric potential energy to thermal energy
C
ground
generator
kinetic energy to electric potential energy
D
lamp
ΔV
potential difference
B
potentiometer
P
power
A
resistor
