P4.4 - Component Characteristics (Finished)

Question 1

Why does the resistance of a filament lamp increase with current?

Answer 1

When an electric charge flows through a filament lamp it transfers some energy to the thermal energy store of the filament (it is designed to heat up). Resistance increases with temperature, so as the current increases, the filament lamp heats up more and current increases

Question 2

What dies the current-potential difference graph for a filament lamp look like?

Answer 2

The line passes through the origin. With increasing p.d. From 0 It curves away from the y axis. It does the same with decreasing p.d. from 0.

Question 3

What does the current-p.d. graph look like for a diode?

Answer 3

With -ive pds the current is 0, in the forwards direction the line stays flat for a bit then curves towards the y -axis

Question 4

Why is a filament lamp not an ohmic conductor?

Answer 4

A filament lamp increases in resistance with increasing current so is not an ohmic conductor

Question 5

What is the charge-p.d. graph like for an LDR and thermistor?

Answer 5

Like a regular resistor providing it is at a contant temperature and light intensity