Section 4 (Electricity) Flashcards
What is the potential difference?
The work done per unit charge.
What two equations include charge?
Q=It
Q=W/V
W- work done
V- p.d
What is the equation for resistance?
R=V/I
What is Ohm’s law?
I is directly proportional to V under constant physical conditions.
What are the Pd-current graphs for an Ohmic conductor, filament lamp and diode?
\_\_
_/ Filament bulb \_\_/
| Diode \_\_\_\_\_\_/
/
____|_____Pd / Ohmic conductor
| /
|A
What is the equation for resistivity?
p=RA/L
p- resistivity
R- resistance
What is superconductivity?
A property of certain materials which have zero resistivity at and below critical temperature with depends on the material.
Superconductors can be used for very strong electromagnets and reduced energy loss in power cables.
What are the 3 equations for power?
P=IV
P=I^2R
P=V^2/R
What equation is used to find the energy transfer in a circuit?
E=IVt
What is meant by the internal resistance of a power source ‘r’?
In a battery, chemical energy is used to make electrons move which collide with atoms inside the battery. Internal resistance is what makes batteries and cells warm up.
What is meant by the electromotive force (e.m.f)?
The amount of electrical energy the battery produces and transfers to each each coulomb of charge.
What is meant by the terminal P.d?
The P.d when one coulomb of charge flows through the load resistance.
What is electric current?
The rate of flow of charge.
How is energy and charge conserved in dc circuits?
As charge and energy flow through a circuit, they don’t get used up or lost. In electrical circuits, energy is transferred.
What happens to current, e.m.f, resistance and voltage in a series circuit?
Current- same at all points
E.m.f- split between components
Voltage- splits proportionally to resistance (V=IR)
Resistance- added up around the circuit
