Question

the resistance of a wire is 10 ohms. find the new resistance if:
the diameter is halved
area is doubled
area is halved
length is doubled
length is halved

Answer 1

$$\begin{gathered} \mathrm{You}\mathrm{can}\mathrm{find}\mathrm{all}\mathrm{these}\mathrm{values}\mathrm{by}\mathrm{using}\mathrm{the}\mathrm{relations}, \\ \mathrm{R}=\frac{\mathrm{\rho l}}{\mathrm{A}} \\ \mathrm{Or}\mathrm{R}=\frac{\mathrm{\rho l}}{{\mathrm{\pi r}}^2}\mathrm{or}\mathrm{R}=\frac{\mathrm{\rho }\mathrm{l}}{\mathrm{\pi }(\mathrm{d}/2{)}^2} \end{gathered}$$