题目4单选题
如图3所示,在无限长载流直导线附近做一个球形闭合曲面<img src="https://p.ananas.chaoxing.com/star3/origin/abe69d9d45af0d9da784ce6d91b72771.png">,当球面<img src="https://p.ananas.chaoxing.com/star3/origin/abe69d9d45af0d9da784ce6d91b72771.png">向着长直导线靠近时,穿过球面<img src="https://p.ananas.chaoxing.com/star3/origin/abe69d9d45af0d9da784ce6d91b72771.png">的磁通量<img src="https://p.ananas.chaoxing.com/star3/origin/85fc29039301abfdd6d3566f3c36123b.png">和面上各点的磁感应强度<img src="https://p.ananas.chaoxing.com/star3/origin/5931c457fbb8dda8474c739ef294f33b.png">的大小将 【 】<img src="https://p.ananas.chaoxing.com/star3/origin/3c14cc99a2a1f10c8e164278d348b993.png">A. <img src="https://p.ananas.chaoxing.com/star3/origin/85fc29039301abfdd6d3566f3c36123b.png">、<img src="https://p.ananas.chaoxing.com/star3/origin/5931c457fbb8dda8474c739ef294f33b.png">均不变B. <img src="https://p.ananas.chaoxing.com/star3/origin/85fc29039301abfdd6d3566f3c36123b.png">、<img src="https://p.ananas.chaoxing.com/star3/origin/5931c457fbb8dda8474c739ef294f33b.png">均增大C. <img src="https://p.ananas.chaoxing.com/star3/origin/85fc29039301abfdd6d3566f3c36123b.png">增大,<img src="https://p.ananas.chaoxing.com/star3/origin/5931c457fbb8dda8474c739ef294f33b.png">不变D. <img src="https://p.ananas.chaoxing.com/star3/origin/85fc29039301abfdd6d3566f3c36123b.png">不变,<img src="https://p.ananas.chaoxing.com/star3/origin/5931c457fbb8dda8474c739ef294f33b.png">增大