题目内容
使用照相机拍摄清晰满意的照片,必须选择合适的曝光量。曝光量P可以表示为:
P=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711017466.gif)
,式中
为常数,
为照相机镜头“通光孔径”的直径,
为照相机镜头的焦距,
为曝光时间,将
的倒数
称为照相机的光圈数。一摄影爱好者在某次拍摄时,选择的光圈数是8,曝光时间是
s。若他想把曝光时间减少一半,但不改变曝光量,那么光圈数应选择( )。
P=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711017466.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711064185.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711251199.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711283198.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711314199.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711064185.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711329241.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711345240.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121711470260.gif)
A.4 | B.5.6 | C.8 | D.11 |
B
略
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目
题目内容
A.4 | B.5.6 | C.8 | D.11 |