(a)[2]
Using Fig. 5.1, describe how the diode’s resistance changes between $V = -0.5\,\text{V}$ and $V = 0.8\,\text{V}$.
(b)[2]
On Fig. 5.2, sketch how current $I$ varies with p.d. $V$ for a filament lamp. No numerical values are needed.
(c(i))[1]
Calculate the resistance of the lamp when the p.d. across it is $12\,\text{V}$. The filament lamp has a power of $36\,\text{W}$ when the p.d. across it is $12\,\text{V}$.
(c(ii))[3]
After the switch is closed, the current in the lamp is $2.8\,\text{A}$. Calculate the resistance of the lamp.
(d)[1]
Explain how the two resistance values calculated in (c) provide evidence for the shape of the sketch you drew in (b).