Electricity and Electromagnetism Flashcards
What is charge measured in?
Coulombs (Q)
Electric field strength is can be seen as two different ratios. What is Field Strength (E) equal to?
E= V/d (volts per meter)
or
E= F/q (Newtons per coulomb)
What is potential gradient?
The rate at which voltage changes (v/d). as E= v/d, potential gradient can be seen as field strength.
What charge do electric field lines always point to?
Negative
What pole do magnetic field lines always point to?
South
Electric Potential energy in an electric field is equal to what?
Field strength times charge times distance (EQD)
What is the movement of charged particles called?
Current (amps)
In what direction does convention current run?
From positive to negative
What is the basic equation for current?
I= q/t (current per unit of time)
voltage is equal to ▲E/q. What does this mean in real terms?
Voltage can be seen as how much potential energy each coulomb of charge has (it is almost like the electromotive force on the electrons)
If two 1.5 volt cells are in series, what is the total circuit voltage?
3 volts (voltage is added when in series)
What is the equation for force on a charged particle in an electrical field
F=Eq
In a series circuit, how would you describe current in the circuit?
It is the same at all points in the circuit.
The sum of the voltages across components in a series circuit is equal to…
The total circuit voltage
In a parallel branch of a circuit, current is divided, and…
Rejoins at the same amount at which is split.
Voltages for two components in parallel will be…
The same ( V=IR, R is constant and I changes proportionally to R, so V is constant)
Ohm’s law is…
V=IR
What is the relationship between resistors in series?
Rt = R1 + R2 + R3….
What is the relationship between resistors in parallel?
1/Rt= 1/R1 + 1/R2 + 1/R3…
What is power?
Energy transferred (work done) over time (in this case, ▲E/t)
If a conductor is ohmic, what does this mean?
Resistance is constant (voltage and current increase in turn with each other)
What is energy transferred equal to?
E = V x I x t
What is power equal to?
P = V x I
Moving electrons cause a…
magnetic field
What “rule” determines the magnetic field caused by a wire with current flowing through it?
The right hand grip rule
Thumb = conventional current direction
Fingers = Magnetic field lines
What is the equation for the force exerted by a magnetic field on a charged particle?
F=BQV
F = force
q = charge on particle
v = velocity of particle
What rule helps you determine the direction of force on a positive particle on a magnetic field?
Right hand slap rule
Palm = force
Fingers = field lines
thumb = direction of velocity (remember, conventional current is + particles)
What rule helps you determine the direction of force on a negative particle on a magnetic field?
Right hand slap rule
Palm = force
Fingers = field lines
Thumb = OPPOSITE OF direction of velocity
What rule helps you determine the direction of force on a wire?
Right-hand slap rule
