练习1:电荷线密度为λ的无限长带电直线的电-|||-场强度分布-|||-dfrac (lambda )(2pi {varepsilon )_(0)}-|||-(B dfrac (lambda )(2pi {{varepsilon )_(0)}^r}-|||-○ dfrac (lambda )(2pi r)-|||-D dfrac ({{u)_(0)}^lambda }(2pi r)

(B) dfrac (lambda )(2pi {varepsilon )_(0)a}. (C) dfrac (lambda )(4pi {varepsilon

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

U=0 (B) E=0 , =dfrac (9)(2pi {varepsilon )_(0)a} q q-|||-(C) =dfrac (q)(2pi {var

dfrac (qQ)(4pi {varepsilon )_(0)(d)_(1)} B. dfrac (qQ)(2pi {varepsilon )_(0)(d)_

(B) dfrac (9)(2pi {c)_(0)(y)^2} - y 个-|||-P(0,y)-|||-+q-|||-(C) dfrac (qa)(2pi {

dfrac (qQ)(4pi {varepsilon )_(0)l} C. dfrac (qQ)(2pi {varepsilon )_(0)l} D. -dfr

3.-|||-一长度为L的带电细棒,P点距离棒左端为a,电荷-|||-分布的线密度 lambda =((a-x))^2, 则P点电场强度大小为:-|||-A d

如图，入射波的波函数为=Acos (omega t-dfrac (2pi )(lambda )x)-|||-__ __，在=Acos (omega t-dfra

9.沿着相反方向传播的两列相干波,其波动方程为 _(1)=Acos 2pi (vt-dfrac (x)(lambda )) _(2)=-|||-cos 2pi

(B) dfrac (9)(2pi {c)_(0)(y)^2} - y↑-|||-(0,y)-|||-+q-|||-(C) dfrac (qa)(2pi {va