洗毛巾的时候一般放多少洗衣粉？多久放一次？为什么？_爱下问搜题

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问题问答题简答题

洗毛巾的时候一般放多少洗衣粉？多久放一次？为什么？

答案

参考答案：

内饰和玻璃毛巾，漆面毛巾一般4天左右放一次，门边及比较脏的毛巾一般2天放一次。因为洗衣粉会破坏毛巾的结构导致不吸水，所以不能常用洗衣粉洗。

完形填空

“I can’t believe what I’m hearing! ”I thought to myself. Jeff was the last candidate（候选人）for president of Student Union. I really thought I should be chosen.
Later that day, I happened to pass Jeff in the dining room. I offered       a polite “Congratulations” and walked to my usual table. To my      , Jeff came to me and put his plate beside mine.
“I’m, er-I’m just wondering if you would consider coming to work on my team, ”he said nervously. “You are really       and you would be a great partner.”
“I don’t think so,” I replied, feeling unsure.
“Well,       you change your mind, you can tell me tomorrow. ”He said before moving to another table.
All that night, I thought about the       from Jeff. Maybe being a part of the election process（选举过程）would give me a chance to make important changes at our school. I decided to       Jeff.
     of all, I began to create a catchy advertisement. Within a few days, we       a poster with Jeff’s showing him in a number of activities. No one could walk through any hallway       passing Jeff’s smiling face.
My next step was to       what new activities students would like to have at our school. Many of them wanted a chess club and a volleyball team.
With the information I had collected, Jeff met with the headmaster. The headmaster agreed to add       we want to our school program.
With my help, Jeff and our ideas were well received at school.
An eighth grader said, “     will be exciting to have Jeff as president.”
     these words made my heart filled with pride. I had wanted to become president of Student Union to make a difference. Now I achieved that. Jeff became the most popular candidate and I was a large part of his      . The fact that it has made a       in other people’s lives is the real prize. What a great feeling!

计算题

如图所示，50匝矩形线圈ABCD处于磁感应强度大小T的水平匀强磁场中，线圈面积S=0.5m²，电阻不计。线框绕垂直于磁场的轴OO′以角速度ω="200" rad/s匀速转动，线圈中产生的感应电流通过金属滑环E、F与理想变压器原线圈相连，变压器的副线圈线接入一只“220V，60W”灯泡，且灯泡正常发光，求:

(1).线圈中产生交变电压的有效值为多少?

(2).变压器原、副线圈匝数之比为多少?

(3).与变压器串联的交流电流表的示数为多少?维持线圈匀速转动输入的最小机械功率为多少?