如图5所示,两个同心的均匀带电球面,内球半径为<img src="/lqwvjeImg/32/326cb8bd5b829e255cbc2b392638e478.png" style="width:18px;height:22px;" >,带电量为<img src="/lqwvjeImg/f6/f6bb882842f19813ee360702fea536e3.png" style="width:18px;height:22px;" >;外球面半径为<img src="/lqwvjeImg/97/97559c97351ed1751ecd1f21d0870efa.png" style="width:20px;height:22px;" >,带电量为<img src="/lqwvjeImg/80/80627770c05545fd18be9bbfc8a63825.png" style="width:21px;height:22px;" >。设无穷远处为电势零点,则在外球面外面,距离球心为r处的点的电势为:( )<img src="/lqwvjeImg/1f/1f3d4f98940adc3d32e1b6cd542856e0.png" style="font-size: 20px;" ><br>· <img src="/lqwvjeImg/61/614eeefc5038cde636c6ed6f364b2b08.png"style="width:57px;height:46px;"><br>· <img src="/lqwvjeImg/4a/4a8969f22646c5142fffdc80453097b0.png"style="width:57px;height:46px;"><br>· <img src="/lqwvjeImg/a8/a866d71812aaad80da1e109efa5d45b5.png"style="width:109px;height:46px;"><br>· <img src="/lqwvjeImg/06/0615769b49e39988ff5a6c9b4191b8c8.png"style="width:45px;height:46px;">