有两根圆轴，一根是实心轴，一根是空心轴。它们的长度、横截面面积、所用材料、所受转矩m均相同。若用<img src="/Image1/6f/6f621007c94de95d664e761f141ea9fc.jpg" />和<img src="/Image1/52/522d38abcc5b68b6865fb0889eac44bb.jpg" />分别表示实心轴和空心轴的扭转角，则二者间的关系是（）<br>A:<img src="/Image1/6f/6f621007c94de95d664e761f141ea9fc.jpg" />=<img src="/Image1/52/522d38abcc5b68b6865fb0889eac44bb.jpg" /><br>B:<img src="/Image1/6f/6f621007c94de95d664e761f141ea9fc.jpg" />＜<img src="/Image1/52/522d38abcc5b68b6865fb0889eac44bb.jpg" /><br>C:<img src="/Image1/6f/6f621007c94de95d664e761f141ea9fc.jpg" />＞<img src="/Image1/52/522d38abcc5b68b6865fb0889eac44bb.jpg" /><br>D:<img src="/Image1/6f/6f621007c94de95d664e761f141ea9fc.jpg" />与<img src="/Image1/52/522d38abcc5b68b6865fb0889eac44bb.jpg" />的大小无法比较