Electricity 1

Question 1

kilowatt-hour

Answer 1

unit of energy equal to 3.6MJ

Question 2

resistance

Answer 2

potential difference across a component divided by the current through it

Question 3

mean drift velocity (of electrons in a wire)

Answer 3

average displacement travelled of the electrons along a wire per second (1/3 marks) where they move slowly in one direction through the metal lattice (2/3) and collide constantly with the lattice (3/3)

Question 4

EMF (electromotive force)

Answer 4

energy transformed from other forms to electrical (1/2 marks) per unit charge (2/2)

Question 5

terminal potential difference

Answer 5

the energy transformed from electrical to other forms (1/2 marks) per unit charge (2/2)

Question 6

Kirchhoff’s 1st law

Answer 6

total currents into a junction equals the total current out

Question 7

Ohms law

Answer 7

current through a component is directly proportional to the current through it providing the temperature, and other physical constants, remain constant. a graph of I against V is a straight line through the origin

Question 8

power

Answer 8

energy transferred per unit time

Question 9

conventional current

Answer 9

current that flows from the positive terminal of a cell to the negative terminal

Question 10

electron flow

Answer 10

the movement of electrons from the negative terminal to the positive terminal

Question 11

resistivity

Answer 11

resistivity of a material is equal to
(resistance of material x cross sectional area of material) / length of material