一太阳能电池板，直接用理想电压表测得它两极的开路电压为0.8V，理想电流表测出的短路电流为0.04A，此电源内阻为____Ω．若将该电池板与一阻值为20Ω的电阻器连成一闭合电路，则流过电阻的电流为____ A．

分类、类比是初中化学常用的学习方法．

阅读下面古诗。
                                                                                                  陇西行 陈陶
                                                                                              誓扫匈奴不顾身，

                                                                                              五千貂锦丧胡尘。

                                                                                              可怜无定河边骨，

                                                                                              犹是春闺梦里人。