hideously important voltage current graphs

Question 1

metal filament lamp:

Answer 1

as the temperature of the metal filament lamp increases, the resistance increases

Question 2

wire:

Answer 2

the current through a wire (at a constant temperature) is proportional to voltage

Question 3

diode:

Answer 3

current will flow through a diode in one direction

Question 4

different resistors:

Answer 4

the current through a resistor (at a constant temperature) is proportional to the voltage. different resistors have different resistances. that will be evident on the graph.