A.2cm2 B.5cm2 C.10cm2 D.25cm2
A.1~2m B.1~3m C.3~5m D.5~10m
A.L=λ2 B.L=λ4 C.L=λ/4及偶數(shù)倍 D.L=λ4及奇數(shù)倍