Electrostatics Flashcards
What does Coulomb’s law measure?
Coulomb’s law measures the force of attraction between charges
Fe=kq1q2/r^2
Where k is constant 9x10^9 Nm^2/C^2
How do we find the force of an electric field?
The magnitude of an electric field
Is given by E=V/d volt/distance= V/m
It also given by E=F/q force/charge N/C
So F=qE
How do we find the electric field for a point charge?
E=kq/r^2
Derived from Coulomb’s law.
Which direction do Electric field lines flow
They flow from away from positive and toward negative or from positive to negative
What does electrical potential measure?
It is a measure of the amount of energy per charge
1V=1 Joule/ Coulomb
Volts at a certain point in space=electric potential
V=kq/r
What is the difference between electric potential energy and electric potential (voltage)?
Electric potential energy is the difference between volts or the change in volts between two points. ◊V
Electric potential measures the force per charge (volts) at a single point
You can find electric potential energy by multiplying the point charge(q) by the electric potential (V)
Where might there be an zero electric field?
It would have to be infinitely away from the charges
Where might there be zero electric potential
It would be where the voltage of the negative is equal to the voltage of the positive in dipole. If the charges are equal then it would be in the middle of the dipole
What’s the difference between an electric field and a magnetic field?
An electric field measures force on a stagnant or still charge whereas magnetic field measures force on a moving charge
How do you calculate magnetic field
1T=Ns/mC
Fb=qVB*sin theta
What is the magnetic field force on a particle moving parallel or anti parallel to the magnetic field
At 0 and 180 the force is 0. Instead the field pushes on the particle at a 90 degree angle (perpendicular to the particles motion and magnetic field) This the Lorentz force.
How does a charge move when it is completely in a magnetic field?
It moves in a circle. This means it has centripetal force.
Fc=mv^2/r
So mv^2/r=qvBsinø so qB=Mv/r
A unknown material is exposed to a magnetic field. A few moments later the material becomes highly magnetized. How would this material be categorized?
This material is ferromagnetic. It has unpaired electrons that orient to create a dipole but doesn’t create a magnetic field itself. However, when exposed to magnetic fields under certain temperatures, it will become highly magnetized.
How does electric potential energy change as like charges move toward each other? What about apart?
Potential energy will decrease as like charges move apart and increase as they move toward each other.
Like charges repel💔 each other so they are in a hurry to get away from each other. In a hurry=increased KE which means decreased PE.
Likewise, it takes more kinetic energy to move them toward each other meaning more kinetic energy is converted to potential energy (increase in PE)
Potential energy will decrease as opposite charges move toward each other and increase as they move away.
Opposite charges ❤️ each other, so it takes more KE to break them up. The more KE used the more it is converted to PE (increase in PE) as they move apart.
What is the charge of a proton/electron
1.6x10^-19
