高二物理競(jìng)賽等勢(shì)面課件

等勢(shì)面等勢(shì)面:電勢(shì)相等的點(diǎn)所組成的曲面靜電場(chǎng)中等勢(shì)面特點(diǎn):帶電體帶電體+++++++E電電場(chǎng)場(chǎng)線(xiàn)線(xiàn)等等勢(shì)勢(shì)面面

電場(chǎng)強(qiáng)度（或電場(chǎng)線(xiàn)）與等勢(shì)面處處正交。較密集；電場(chǎng)強(qiáng)度小的地方電場(chǎng)強(qiáng)度大的地方等勢(shì)面等勢(shì)面較稀疏。0EE0Ese0ss+-d電荷面密度X0附加如圖示兩“無(wú)限大”均勻帶電平行平面若選正電平面為零勢(shì)面求、、區(qū)電勢(shì)分布U()ixhd0Ex0x0U()hx0idxEx0se0ihidxse0xxd0dU()xEhidx+d0Ehidxse0dxd0VXd等勢(shì)等勢(shì)用電勢(shì)定義法求一對(duì)均勻帶等量異號(hào)電荷等半徑共軸圓環(huán)圓心間的電勢(shì)差x+0RXR0qqaIIIx0e4pq+R22x)(23xEIxEIIx0e4pq+R2232x)(axEIxEII+xEx0e4pq+R22x)(23a0dx+a0x0e4pq+R2232x)(adx0e4pqR2+x21+R2+2x)(a10a20epqR)(1R2+21a等勢(shì)2.電場(chǎng)線(xiàn)和等勢(shì)面正交證：設(shè)等勢(shì)面上任一點(diǎn)P處電場(chǎng)強(qiáng)度為

因均不為零點(diǎn)電荷q0在P點(diǎn)沿等勢(shì)面位移時(shí)有證：設(shè)點(diǎn)電荷q0沿等勢(shì)面從a點(diǎn)移到b點(diǎn)則1.沿等勢(shì)面移動(dòng)電荷，電場(chǎng)力不作功點(diǎn)電荷勢(shì)場(chǎng)等勢(shì)面等勢(shì)面場(chǎng)電線(xiàn)電場(chǎng)線(xiàn)+電偶極勢(shì)場(chǎng)+-電場(chǎng)線(xiàn)電場(chǎng)線(xiàn)等勢(shì)面等勢(shì)面電容器勢(shì)場(chǎng)++++++++++++++++++電場(chǎng)線(xiàn)等勢(shì)面電導(dǎo)塊勢(shì)場(chǎng)等勢(shì)面等勢(shì)面電場(chǎng)線(xiàn)電場(chǎng)線(xiàn)++++++++++++++++++++++++++++++++++

電場(chǎng)強(qiáng)度與電勢(shì)的關(guān)系單位正電荷從P移到Q時(shí)設(shè)兩個(gè)相距很近的等勢(shì)面1和2，電勢(shì)分別為U和U＋dU(dU>0)設(shè)P點(diǎn)處沿法向

時(shí)，即沿從P到R負(fù)號(hào):的方向與原設(shè)方向相反——電勢(shì)降方向回顧：FiFx+jyF+kzFeeEpxieeEpyjeeEpzkEp其中為(nabla)eexiyjzk+eeee+Ep稱(chēng)為勢(shì)能梯度結(jié)論：保守力等于勢(shì)能梯度的負(fù)值?！茴D算符

在直角坐標(biāo)系中討論：(1)在U不變的空間，電勢(shì)梯度為零，則必為零(2)U