flascard Flashcards
What are the three particles that make up an atom?
Electron, Proton, Neutron
What is the core of an atom called?
Nucleus
What force holds protons and neutrons within the nucleus?
Strong nuclear force
What holds negatively charged electrons within the atom?
Attractive electric forces exerted by the positively charged nucleus
Define electrostatic force.
Attractive or repulsive force between two electrically charged objects
What are the interactions called between electric charges that are at rest?
Electrostatics
What is the mass of a proton?
1.672621898(21) x 10^-27 kg
What is the mass of a neutron?
1.674927471(21) x 10^-27 kg
What is the mass of an electron?
9.10938356(11) x 10^-31 kg
What is the net electric charge of a neutral atom?
Zero
What is the atomic number?
Number of protons or electrons in a neutral atom of an element
What is a positive ion?
An atom that has lost one or more electrons
What is a negative ion?
An atom that has gained one or more electrons
What is the process of gaining or losing electrons called?
Ionization
List the methods of charging.
- Charging by friction
- Charging by conduction
- Charging by induction
What occurs during charging by friction?
Transfer of electrons when objects are rubbed against each other
What is the triboelectric series?
List of objects and their tendency to give up or take electrons when charged by friction
State the law of charges.
Like charges repel; unlike charges attract
What is the conservation of charge?
The algebraic sum of all electric charges in a closed system is constant
What is charging by conduction?
Transfer of electrons from a charged object to another by direct contact
Define conductors.
Materials whose electric charges are free to move within
Define insulators.
Materials in which electric charges are NOT free to move within
What happens during charging by induction?
Movement of electrons to one part of an object by the electric field of another object
What does Coulomb’s Law state?
The electric force between two charges is proportional to the product of the charges and inversely proportional to the square of the distance between them
What is the value of k in Coulomb’s Law?
8.9875 × 10^9 N.m²/C²
Fill in the blank: In a neutral atom, the number of _______ equals the number of protons.
Electrons
Fill in the blank: A charge of _______ is the charge of an electron.
-1.60 x 10^-19 C
Fill in the blank: A charge of _______ is the charge of a proton.
1.60 x 10^-19 C
What is the charge of an ion with two missing electrons?
Positive charge of +3.20 x 10^-19 C
What is the net electric force on a point charge affected by other charges?
It is calculated based on the individual forces exerted by each charge
True or False: The net electric force in a closed system can change.
False
What happens when two point charges have the same sign?
They repel each other
What happens when two point charges have opposite signs?
They attract each other
What is the formula for calculating electric force per unit charge experienced by a charge at a certain point?
Electric force per unit charge = Electric field
The electric field is defined as the force experienced by a unit positive charge at a point in space.
The electric field of a point charge always points ______ from a positive charge.
away
This indicates that positive charges repel other positive charges.
The electric field of a point charge always points ______ toward a negative charge.
toward
This indicates that negative charges attract positive charges.
What is conventional current?
The flow of electric charge from positive to negative
Conventional current considers the direction of flow of positive charges.
What is the unit of electric current?
Amperes (A)
Current is defined as the time rate of flow of electric charge.
Voltage is also known as ______.
electric potential difference
Voltage measures the work needed to move a charge between two points.
What is the unit of voltage?
Volts (V)
Voltage quantifies the potential energy per unit charge.
Define resistance.
The opposition to the flow of charge
Resistance occurs due to collisions within the conducting material.
What is the unit of resistance?
Ohms (Ω)
Resistance quantifies how much a material opposes the flow of electric current.
What does Ohm’s Law describe?
The relationship between voltage, current, and resistance
Ohm’s Law states V = I × R.
When current exists in a circuit, what is done to overcome resistance?
Work is done and power is expended
This relates to the electric power generated in the circuit.
What is the formula for electric power in a circuit?
Power (P) = Voltage (V) × Current (I)
Power is measured in watts (W).
If a circuit has a resistance of 18 Ω and a current of 15 A, what is the rate of energy per Coulomb?
V = I × R = 15 A × 18 Ω = 270 V
This calculation uses Ohm’s Law.
If the voltage is 300 V and the resistance is 0.5 Ω, what is the current?
I = V / R = 300 V / 0.5 Ω = 600 A
This calculation also uses Ohm’s Law.
A 12 V socket produces 120 Coulombs of charge per second. What is the resistance of the wire?
R = V / I = 12 V / 120 A = 0.1 Ω
This calculation determines the resistance based on voltage and current.
List materials that are conductors.
- Copper
- Au
- Ag
- Beryllium
Conductors allow the flow of electric current easily.
List materials that are insulators.
- Rubber
- Glass
- Pure water
- Hair
- Human skin
- Paper
Insulators resist the flow of electric current.
