Gold $({}_u)$ has Face center cubic crystal at room temperature with atomic radius is $1\mathrm{.}52,$ and its atomic weight is $196\frac{g}{m}ol.(N_a$ is $6\mathrm{.}02{10}^{23}$ :

a$)$ Calculate its lattice parameter.

b$)$ What is its density?

c$)$ Calculate its APF at room temperature.

d$)$ Calculate its APF at $960C$ temperature