Question

如圖所示，有一對(duì)等量異種電荷分別位于空間中的a點(diǎn)和f點(diǎn)，以a點(diǎn)和f點(diǎn)為頂點(diǎn)作一正立方體．現(xiàn)在各頂點(diǎn)間移動(dòng)一試探電荷，關(guān)于試探電荷受電場(chǎng)力和具有的電勢(shì)能以下判斷正確的是（　　） A．在b點(diǎn)和d點(diǎn)受力相同 B．在c點(diǎn)和h點(diǎn)受力相同 C．在b點(diǎn)和d點(diǎn)電勢(shì)能相等 D．在c點(diǎn)和h點(diǎn)電勢(shì)能相等

Answer 1

A、根據(jù)等量異種電荷電場(chǎng)線的分布情況和對(duì)稱性可知，b點(diǎn)和d點(diǎn)場(chǎng)強(qiáng)大小相等、方向不同，則試探電荷在b點(diǎn)和d點(diǎn)受力大小相等，方向不同．故A錯(cuò)誤．
B、c點(diǎn)和h點(diǎn)場(chǎng)強(qiáng)大小相等、方向相同，則試探電荷在c點(diǎn)和h點(diǎn)受力大小相等，方向相同．故B正確．
C、根據(jù)對(duì)稱性可知，b點(diǎn)和d點(diǎn)電勢(shì)相等，則試探電荷在b點(diǎn)和d點(diǎn)電勢(shì)能相等．故C正確．
D、由圖看出，c點(diǎn)離場(chǎng)源正電荷較遠(yuǎn)，而h點(diǎn)離場(chǎng)源正電荷較近，所以c點(diǎn)和h點(diǎn)電勢(shì)不等，則試探電荷在c點(diǎn)和h點(diǎn)電勢(shì)能相等．故D錯(cuò)誤．
故選：BC