Supposetherearetwoelectricitytesters,AandB(FigureA).AndametalcylinderCwhichisalmostclosed(calledFaradayCylinder)isfixedtotesterB,makingbothtesterBandcylinderCcharged.Asaresult,thealuminiumfoilontesterBopens.
中学生语数外:高中版
2004年11期