Electric Circuits Flashcards
- Equation for a Current
Current(I) = change in Charge (Q)/ change in Time(T)
UNITS FOR EQUATION? CURRENT
Current (I) (Amp)
Charge (Q) (Coulombs)
Time (T) (sec)
WHICH WAY DOES THE CURRENT FLOW?
It flows from the negative terminal to the positive terminal.
WHAT IS ELECTRICITY?
It is the flow of electrons in the wire that constitute the current
WHAT IS THE ELECTRON CHARGE ?
1.6 X 10^-19 (C) Coulombs
- WHAT IS THE EQUATION FOR VOLTAGE?
Voltage (V)=Work Done (W)/ Charge (q)
UNITS OF EQUATION VOLTAGE
Voltage (V) (Volts)
Work Done (W) (Joules)
Charge (Q) (Coulomb)
- OHMS LAW EQUATION FOR PD
V (cell) = I (in the wire) R (resistor)
- WHAT IS CHARGE CONSERVATION?
principle that total electric charge in a isolated system never changes
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- FORMULA FOR RESISTIVITY FOR A WIRE?
RESISTANCE =
P(resistivity) X LENGTH (L) / CS AREA
- FORMULA FOR THE LARGE RANGE OF RESISTIVITY?
I=NAVE N= I/AVE
UNITS FOR LARGE RANGE OF RESISITIVITY
I=CURRENT=AMPS N=ELECTRON DENSITY A=CS AREA V= VELOCITY E=CHARGE 1.6 X 10^-19 C
RESISTANCE CALCULATIONS FORMULA PARALLEL
FOR EACH ARE 1/R = 1/R1 + 1/R2 (1/R RECIPRICOL)
What is Potential Difference
PD IS V =IR
Formula to find Charge
(Q)charge = NE (no if e)(charge) = IT
Equation for power
Power = Voltage x Current. Power = Work Done x Time
Equation for work done
W (work done) = VI (Power) x T
- Resistance
What is Ohms Law ?
If Ohms Law is obeyed, the current and voltage passing through a component are directly proportional, when at a constant temperature
Describe the distribution of current in a series circuit
In a series circuit, the current stays the same at all positions in the circuit
What law does distribution of current in a series obey?
The Law of Conservation of Charge. Charge cannot be created or destroyed and so is in a closed loop
:. The flow of the charge should be the same throughout.
Describe the distribution of current in a parallel circuit.
In a parallel the current is split between the different branches. The current entering in each branch should be the same as the current leaving the branch.
Potential Difference in series and parallel.
The P.d. In a series is split, in parallel it is the same around all the components.
What is the IV of ohmic conductor?
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| _/\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_What is the IV characteristics for filament bulb?
Graph_
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What is the IV characteristics for a diode?
Graph /
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Energy Efficiency formula
Useful / total X 100
Upward force on something
Normal contact force
Newton’s first law
A body will remain at rest or constant velocity unless it is acted upon by a net external resultant force.
Newton’s second law
Acceleration of a body with constant mass is related to the net external force acted on the body
F=MA
RESULTANT FORCE = MASS X ACC
Newton’s third law
When a body exerts a force on another body second body exerts a force back on the first body with the same magnitude same type in a straight line opposite direction as the force exerted by the first body
Moment
Moment = force x distance (from the from the pivot perpendicular to forces line of action)
Kg to N mass to force
1 kg is equal to 9.81 N
Momentum P
Momentum (P) = Mass X Velocity
Electromotive force
Electromotive force is work done per unit charge to move a charge around a circuit
