dfrac (pi {R)^2E}(2)-|||-C.2πR^2E-|||-D.0

dfrac (1)(2)pi (R)^2E-|||-D. sqrt (2)(R)^2E-|||-E. dfrac (pi {R)^2E}(sqrt {2)}

-(pi R)^2E-|||-E-|||-R-|||-图1

[ dfrac {{e)^2}({(z-1))^2},1] =-|||-A e-|||-B dfrac (1)(e)-|||-C dfrac (e)(2)-||

dfrac ({U)_(0)I}(2R)-|||-D . dfrac ({U)_(0)I}(2pi R)

3、若匀强电场的场强为E,其方向平行于半径为R的半球面的轴,-|||-如图所示。则通过此半球面的电场强度通量φe为-|||-(A)πR^2E (B)2πR^2E

一电场强度为E的均匀电场，E的方向与x轴正向平行，如图所示，则通过图中一半径为R的半球面的电场强度通量为（）。 A．πR2EB．π

3.若抛物线 =a(x)^2 与曲线 =ln x 相切,则 a= () () .-|||-(A) dfrac (1)(2e) (B)2e (C) dfrac (

=dfrac (Q)(4pi {varepsilon )_(0)r}-|||-(D) =dfrac (Q)(4pi {varepsilon )_(0)(r)^2

U=0-|||-(B) E=0 . =dfrac (q)(2pi {varepsilon )_(0)a}-|||-(C) =dfrac (q)(2pi {var

varphi dfrac ({R)^2}({r)^2}-|||-C.O-|||-○ D. circled (1)(dfrac ({R)^2}({r)^2}-1)