小明在镜子里看到自己的像在用右手拿着梳子向左梳头，那么他实际

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问题选择题

小明在镜子里看到自己的像在用右手拿着梳子向左梳头，那么他实际是（　　）

A．用右手向左梳头

B．用左手向右梳头

C．用右手向右梳头

D．用左手向左梳头

答案

根据镜面对称的性质，当你面对镜子的时候，右手拿着梳子向左梳头，对于镜子中的像来说是左手拿着梳子，向右梳头．

故选：B．

填空题

竖直放置的两块平行金属板A、B，分别跟电源的正负极连接，将电源正极接地，如图所示．在A、B中间固定一个带正电的电荷q，现保持A板不动，使B板向右平移一小段距离后，电荷q所在位置的电势U将______，电荷q的电势能ε将______．（填：变大、变小或不变．）

单项选择题

Which maintenance functions can a GMDSS Radio Operator perform（）.

A.The Operator can make fine internal adjustments to the transmitter as long as the output power does not change by more than one percent

B.The Operator is responsible for ensuring that INMARSAT antennas are free of built-up soot and clear of obstacles

C.All levels of maintenance must be performed by a licensed GMDSS Radio Maintainer

D.The Operator may install an EPROM in order to ensure that the equipment continues to operate within legal constraints