(a)visibility=\(\frac{2 \sqrt{I_1 I_2}}{I_1+I_2}=\frac{2E_{01} E_{02}}{E_{01}^2+E_{02}^2}=\frac{2(1.6)(2.8)}{(1.6)^2+(2.8)^2}=0.86\)

(b)\(I_{12}=E_1*E_2=0\)

visibility=0