Physics Revision 3

Electrical field, electrical charge

I

electrical current [Amps]

Q

electric charge [Coloumb]

field

a region in which a charge experiences an electrical force.

electrical field strength

force per unit change experienced by a charge. [N/C]

electrical field equation

Efield: F/Q

electrical current

movement of charge per unit time.

electrical current equation

I=Q/t [A=C/s]

electrical power

electrical energy transformed per unit time.

basic power equation

P=E/t [W=J/s]

electrical power equation

Pelec=VxI [W=VxA]

electrical voltage

energy transformed per unit charge.

electrical voltage equation

V=E/Q [V=J/C]

Ohm's Law

V=IR

Power equation

P=VI

Resistance in series

Rt=R1+R2

Resistance in parallel

1/Rt=1/R1+1/R2+...

Factors that affect resistance

length, cross-sectional area, resistivity

Energy equation

E=VIt

Resistivity equation

R=L/A (length/x-sectional area)

In a series, ________ is always the same

amps/current

In parallel, ________ is always the same

volts/voltage

low resistance =

high current

Current in a series

current in a series is the same everywhere

Current in parallel

current in=current out (current is shared)

affect of high temperature on current

As temperature increases, the resistance increases because the atoms in the material vibrate more, impeding the flow of electrons. This reduces the current for a given voltage.