如圖所示,勻強(qiáng)電場場強(qiáng)E=100V/m,A、B兩點相距10cm,A、B連線與電場線夾角為60°,則UBA之值為(   )                                                                                                                             

                                                                                                                

    A. ﹣10V       B. 10V   C.                  ﹣5V      D. ﹣5V

                                                                                                                                     

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