Unit 4: Gravity and Electrostatics Flashcards
A positive charge will (attract/repel) another positive charge
repel
A positive charge will (attract/repel) a neutral charge
attract
A positive charge will (attract/repel) a negative charge
attract
A negative charge will (attract/repel) another negative charge
repel
A negative charge will (attract/repel) a neutral charge
attract
Which particle can actually move freely between objects?
electrons (e-)
Electric Charge
A property of matter / some elementary particles
- it gives rise to particle interactions and electricity
Charge that is stationary
electrostatic charge
Charge that moves continuously
electric current
where are protons+ found in the atom?
the nucleus
where are neutrons found in the atom?
the nucleus
where are electrons- found in the atom?
They orbit the nucleus and can move freely
if an atom is neutral, it has __(magnitude of p+ and e-)
the same number of protons and electrons
Objects with excess of electrons are said to be ( positively / negatively) charged
negatively
Objects with a deficiency of electrons are said to be ( positively / negatively) charged
positively
Like charges _____, unlike charges _____.
repel, attract
Conservation of Charge
Charge cannot be created nor destroyed, but it can be transferred.
Charge transfer
reflects the desire to minimize the repulsive forces between excess electrons.
charges transfer more easily through (insulators/conductors)
conductors
Insulators
materials in which electrons do not move freely
Insulator examples
-rubber, wool or silk, plastic, glass, foam
Conductors
material in which electrons move freely
Conductors examples
metal (copper and aluminium)
Charging by Friction
Charging through contact like rubbing
- electrons move because they have been heated and rubbed off
- both objects are neutral
-works with both insulators and conductors
Charging by Conduction
When a charged object touches a charged or neutral object
- works with both insulators and conductors
Polarization
The rearrangement of atoms or molecules resulting in induced charge on neutral object
-balloon ex, paper punches ex
- only works with insulators
Charging by induction
Touch is induced on an object by holding a charged object close by and it is temporary unless you ground it
-only works for conductors
Grounding
Provides a pathway for electrons in a sink (take away) or source (give) of electrons
- it is connected to the Earth
Ways to charge insulators
friction, conduction, polarization
ways to charge conductors
friction, conduction, induction
Electrostatic Force (Fe)
The force that results when two charged objects, near one another, experience acceleration towards or away from each other
Coulomb’s Law of Electrostatic Force
Fe= Kcq1q2/r2
Kc
Coulomb’s constant
8.99 x 10^9 Nm^2/c^2
Electric Field
A force field that surrounds an electric charge or group of charges
What is E?
Electric Field Strength
the magnitude of the electric field
Source Charge (Q)
Alters original space around it producing the field
- field exists because of the source charge
- it’s the charge at the center of the field
Test Charges (q0)
Interact with the field at the location and that it is where you see the force
- usually positive
- small and magnitude compared to the source so that it doesn’t alter the field much
- q0 experiences the field and experience it at different points
What is the direction of E?
the direction of the Fe on a test charge
Uniform Electric Field (UEF)
A field that has the same value and direction at all points
Electric Potential Energy (PEelec)
Potential energy associated with the charge due to its position in an electric field
Electric Potential (V)
The work that must be performed against electric forces to move a charge from a reference point to the point in question divided by the charge
-energy per charge
Electric Potential Difference (^V)
The works that must be performed to move a charge between two points divided by the charge
- the change in electric potential
-voltage
