#### Physics Unit 5

Coulomb (D/U)

the charge transported by a current of 1 ampere in 1 second; C

Conductor (D)

a material that allows charges to flow through easily (a sea of delocalized electrons)

Insulator (D)

a material that doesn't allow charges to flow through easily (very few free electrons)

Electric field (D)

the region around a charged object where other changes experience an (attractive or repulsive) force

Coulomb's law of electrostatic force (D/F)

the electric force between 2 point charges is (1) proportional to the product of their charges and (2) inversely proportional to the square of the distance between them

Electric field strength (D/U/F)

the force per unit charge experienced by a small positive test charge placed in the field; C2m-2

Electric field strength between 2 parallel plates (U/F)

Vm-1

Potential difference (D/U/F)

work done per unit charge to move a quantity of charge across 2 points; V

Electronvolt (D/U)

energy gained by a charge when it is passed through a potential difference of 1 volt; eV

Current (D/U/F)

the rate of flow of charge; A

Heating effect (D)

1) when e- collides with a nucleus in a wire, electrons transfer KE partially to the nucleus 2) average KE of nucleus increases3) temperature increases

Ohm's Law (D/F)

p.d. across a component is proportional to the current flowing through a component at a constant temperature

Resistance (U)

ohm

Resistivity (D/F)

resistance of a material of unit cross-sectional area and unit length

Power (D/U/F)

rate of work done / rate of energy transferred; W

Kirchhoff's first law (D/F)

the sum of the currents entering a circuit junction must equate the sum of the currents leaving the junction (conservation of charge)

Kirchhoff's second law (D/F)

in a closed loop of a circuit, the sum of the e.m.f.s is equal to the sum of the p.d.s