皮皮学，免费搜题
登录
搜题
【简答题】
用双踪示波器观测两个同频率正弦波a，b，若扫描速度为0.20ms/div，而荧光屏显示两个周期的水平距离使8div，问：（1）两个正弦波的频率是多少？ （2）若正弦波a比b相位超前1.5div，那么两个正弦波相差多少？
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】When people are asked what kind of housing they need or want, the question ________ a variety of answers.
A.
defies
B.
magnifies
C.
mediates
D.
evokes
【简答题】Put the verbs in brackets into the c orre c t tense. 1 . We _________ (do) our homework at6.30p.m.yesterday. 2 . They ________ (m ee t) while they _________( study) at university. 3 . l _______ (not l...
【单选题】关于滤线栅栅比叙述正确的是
A.
栅比越大消除的散射线的能力越差
B.
栅比为铅条宽度与其高度之比
C.
栅比为铅条高度与其宽度之比
D.
栅比为单位距离内铅条的数目
E.
栅比表示单位体积中铅的重量大小
【简答题】L4 A Formal Letter Dear Sir/Madam, I am ___1___(write) to ask for more information on the Business English course. I am very ___2___(interest) in the course but I would like some details. Firstly, _...
【简答题】中药片剂的制备工艺一般可分为 、 、 、 四种。
【简答题】Put the verbs in brackets into the c orre c t tense. 1 . We _________ (do) our homework at6.30p.m.yesterday. 2 . They ________ (m ee t) while they _________( study) at university. 3 . l _______ (not l...
相关题目：