问题
单项选择题
波长为λ的单色平行光垂直入射到一狭缝上，若第一级暗纹的位置对应的衍射角为θ=±π/6，则缝宽的大小为（）。
A．3λ
B．2λ
C．λ
D．
答案
参考答案：B
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波长为λ的单色平行光垂直入射到一狭缝上，若第一级暗纹的位置对应的衍射角为θ=±π/6，则缝宽的大小为（）。
A．3λ
B．2λ
C．λ
D．
参考答案：B
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