A.10mm B.7.5mm C.5mm D.2.5mm
A.H1/H2=(n1/n2)3 B.H1/H2=n1/n2 C.H1/H2=(n1/n2)2
A.Q’/Q=D1/D2 B.Q’/Q=D2/D1 C.Q’/Q=2D1/D2