用電的真正意義是?

電池會沒電是因為電在導體中有電阻,慢慢減少電流.

哈哈，我覺得呢句有少少錯，佢無電，
係因為一粒電池既兩邊無左potential different, 姐係電勢差，姐係正極既化學物質既能量水平同負極已經差唔多，
（呢個對於potential different平衡既解釋唔係清楚，不過大約係咁，其他野肯定岩，呢句咁解唔肯定岩唔岩）,

負極已經唔可以再誘發正極物質再發生化學變化，發出帶有能量既電子
（電子有能量係因為一個電池化學作用既生成物既化學能量比本身低左，多左Ｄ能量出黎）

所以其實佢無電同有無電阻一Ｄ關係都無 ==
講落其實呢句錯得好緊要，因為如果你用電線放埋電池兩極，好快會無電
點解用Ｄ細電阻既野Ｄ電池可以用耐Ｄ呢，呢個有少少複雜，哈哈，你開多條問題我再解你聽

不過我唔明，點解你會話電器唔係閉合電路？插頭上面三隻腳一隻入一隻出一隻防溜電，咪有去有回囉

電路聯結了許多不同種類的電機元件於其閉和迴路。在電路的閉和迴路內，由源點傳送出去的電荷必須回到源點，這樣，才能滿足電荷守恆定律。

電路裏的有許多種不同的電機元件，包括電阻器、電容器、開關器（switch）、變壓器和電子元件等等。電子電路的主動元件，大多是半導體，通常會表現出非線性行為，必須用複分析來解析。最簡單的電機元件是線性的被動元件。

可是電器不是一個閉合電路,電流有去沒回,它最終去了哪兒?

如果冇比電佢,佢內面既金屬係全部冇晒電既

"Electricity" is so widely used simply because it can be transformed to other forms of energy by simple devices. For example, a light bulb turns eelctrical energy into light (and heat) energy. A loudspeaker turns eelctrical (signal) energy into sound energy. A motor (such as an eelctric fan) turns electrical energy into mechanical energy.

By the Law of Conservation of Energy, electrical energy must be produced from a "source". For a battery as you said in your question, the electrical energy comes from the chemical energy stored in the elecrolyte in the battery through chemical reactions. When the electrolyte is "used up", the chemical reaction ceases, and no more electrical energy could be supplied. If the circuit is not a "closed circuit", there won't be any energy dissipated on it.