The radius of a uniformly charged conducting sphere is R and the charge quantity is Q. The electric field intensity inside the conductor is
A: 0
B: [img=72x67]1803b96ae92dd57.png[/img]
C: [img=85x67]1803b96af174e3e.png[/img]
D: [img=81x63]1803b96af9c0a88.png[/img]
A: 0
B: [img=72x67]1803b96ae92dd57.png[/img]
C: [img=85x67]1803b96af174e3e.png[/img]
D: [img=81x63]1803b96af9c0a88.png[/img]
A
举一反三
- Assuming [img=44x19]180356bf7bb2407.png[/img] at [img=51x14]180356bf83a35c2.png[/img], the electric potential at the center of a conductor sphere with charge Q and radius R is A: [img=48x47]180356bf8c59ad0.png[/img] B: [img=9x18]180356bf947b6d5.png[/img] C: [img=18x14]180356bf9c04f33.png[/img] D: [img=38x47]180356bfa41dca2.png[/img]
- Point A is a distance L to the left of a charge Q. Point B is adistance 3L to the left of point A. If the electric field atpoint A due to charge Q is E, what is the electric field atpoint B?[img=277x49]17da660b2a21250.png[/img] A: E/3 B: E/9 C: E D: 3E E: E/16
- 设随机变量(X,Y)在区域｛(x,y): 0<|y|< x <2｝内均匀分布，则以下结果正确的是 A: 当0<x<2时，[img=96x25]1802dded7db6eef.png[/img]. B: E(X)=4/3 C: 当0<|y|<2时,[img=105x45]1802dded872b92f.png[/img]. D: P(X<1)=0.5 E: 当0<x<2时,[img=110x45]1802dded915de6e.png[/img]. F: E(X)=2/3 G: 当0<y<2时，[img=95x43]1802dded9a54300.png[/img].
- f(x)在[0,1]上有连续的二阶导数，f(0)=f(1)=0,任意x属于[0,...715af2ac3f81f8.png"]
- 以下集合中是有限集的是（） A: ｛三角形｝ B: ｛x[img=12x17]1802db31c237b71.png[/img]N|x<3｝ C: ｛x|x=2n,n[img=12x17]1802db31c237b71.png[/img]Z｝ D: ｛x[img=12x17]1802db31c237b71.png[/img]R|[img=18x22]1802db31daafa8f.png[/img]+1=0｝
内容
- 0
以下集合中是有限集的是（） A: ｛三角形｝ B: ｛x[img=12x17]1802e8ef52916c1.png[/img]Z|x<3｝ C: ｛x|x=2n,n[img=12x17]1802e8ef52916c1.png[/img]Z｝ D: ｛x[img=12x17]1802e8ef52916c1.png[/img]R|[img=18x22]1802e8ef6aa524c.png[/img]-1=0｝
- 1
设X~U(a,b), a>;0,E(X)=3, D(X)=[img=15x41]17e438378e5b7d7.png[/img], 则P(1<;X<;3)=____。
- 2
设X~U(a,b), a>;0,E(X)=3, D(X)=[img=15x41]17e0a8afbe72bb4.png[/img], 则P(1<;X<;3)=____。
- 3
下列（ ）是谓词公式。 A: P(x) B: [img=12x14]180324c8744588e.png[/img]P(x) C: P(x)[img=18x11]180324c87c59fe1.png[/img]Q(x) D: P(x)+Q(x)[img=18x11]180324c884649c1.png[/img]R(x)
- 4
下列（ ）是谓词公式。 A: P(x) B: [img=12x14]18038f1536a9c9f.png[/img]P(x) C: P(x)[img=18x11]18038f153e625c4.png[/img]Q(x) D: P(x)+Q(x)[img=18x11]18038f1547a3842.png[/img]R(x)