A.λ=6N B.λ=3N C.λ=6N-3 D.λ=3N-3
A.(黑面高差+红面高差)/2 B.(黑面高差+(红面高差±0.1m))/2 C.(黑面高差+(红面高差+0.1m))/2 D.(黑面高差+(红面高差-0.1m))/2