题目

一电流表的量程标定不准确，某同学利用图1所示电路测量该电流表的实际量程。所用器材有：量程不准的电流表，内阻=10．0，量程标称为5．0mA；标准电流表，内阻=45．0，量程1．0mA；标准电阻，阻值10．0；滑动变阻器R，总电阻为300．0；电源E，电动势3． 0V，内阻不计；保护电阻；开关S；导线。回答下列问题： （1）开关S闭合前，滑动变阻器的滑动端c应滑动至               端。 （2）若测量时，未调到满偏，两电流表的示数如图3所示，从图What is color? Why do some of the things around us look red, some green, others blue?Colors are really made by reflected(反射)light. We see color because most of the things reflect light. Something is red, for it reflects most of the red light. In the same way, if something is green, it reflects most of the green light. If something reflects all light, it is white. If it doesn’t reflect any light, it is black.Some of the light is reflected and some is taken in (吸引)and turned into heat. The darker the color is, the less light is reflected, the more light is taken in. So dark-colored clothes are warmer in the sun than light-colored clothes.根据短文内容，判断正(T)误(F)1.When something reflects light, we can see its color.2.Something looks white because it reflects all light.3.The dark-colored clothes are warm because less light is taken in.4.In summer light-colored clothes make people feel cool.5.Color is the best title of this passage.