Calculate id and vd if the polarity of the voltage source

Question

Question:

Regarding the circuit depicted in Fig., compute I. if the diode is modelled:

(a) as an ideal diode;

(b) with the piecewise linear model V₀ = 0.70 V and R₀ = 0Ω.

(c) Calculate I_D and V_D if the polarity of the voltage source is reversed. Use the piecewise model in part (b) and assume a breakdown voltage of -V_BR = 50 V.