Longer wavelength raises the sine marker for the same spacing and order. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Short wavelength closes at one fifth
Spacing 5 m times sine marker 1/5 gives 1 m. Order 1 times wavelength 1 m gives 1 m, so this row is accepted.
5m⋅51=1mmλ=1⋅1m=1mA=1
Double wavelength doubles the marker
Spacing 5 m times sine marker 2/5 gives 2 m. Order 1 times wavelength 2 m gives 2 m, so this row is accepted.
5m⋅52=2mmλ=1⋅2m=2mA=1
Endpoint sine overshoots this wavelength
Spacing 5 m times sine marker 1 gives 5 m. Order 1 times wavelength 3 m gives 3 m, so this row is rejected.