(a)[1]
State what Kirchhoff’s first law says.
(b(i))[3]
Determine the resistance of the diode when the potential difference $V$ is $0.60\,\text{V}$.
(b(ii))[1]
Describe, in qualitative terms, how the resistance of the diode changes as $V$ rises from $0.60\,\text{V}$ to $0.75\,\text{V}$.
(c(i))[1]
Read off $E$ from Fig. 6.1.
(c(ii))[2]
Determine the resistance of resistor Y.
(c(iii))[2]
Calculate the power dissipated in the diode.
(c(iv))[1]
The cell is then replaced by a different cell with e.m.f. $0.50\,\text{V}$ and negligible internal resistance. Use Fig. 6.1 to find the new current in the diode.