【简答题】Writing: Suppose you are a close friend of the Elliott family. Write a letter of condolence(吊唁) to Pauline on the death of Frank. Write a letter of about 130 words.
【简答题】Write a letter of condolence to the patients in Wuhan hospitals with about 150 words.
【单选题】灯具在空间各个方向上的光强的分布情况用()来描述。
【简答题】平行单色光垂直入射到平面衍射光栅上,若增大光栅常数,则衍射图样中明条纹的间距将 ,若增大入射光的波长,则明条纹间距将 。 (两空都填“增大”、“减小”或者“不变”)
【单选题】It isn't ____ cell phone. I left it at home. [ ]
【单选题】—Why! Where’s my mobile phone? Maybe I left it on the plane. —My goodness! You things behind.
【单选题】My mobile phone disappeared. Where _____ I have left it?
【单选题】平行单色光垂直入射到平面衍射光栅上,若光栅常数从每毫米500条变成每毫米600条,则衍射图样中明条纹的间距将 ,若入射光从黄光变成红光,则明条纹间距将 。
【简答题】(1)Write the possible values of l when n=5. (2)Write the allowed number of orbitals (a) with the quantum numbers n=4,l=3;(b) with the quantum numbers n=4;(c) with the quantum numbers n=7,l=6,m=6;(d) w...
【多选题】平行单色光垂直入射到平面衍射光栅上,下列说法正确的是:
A.
若增大光栅常数,则衍射图样中明条纹的间距将变大
B.
若增大光栅常数,则衍射图样中明条纹的间距将变小