平均自由程lambda =1div sqrt (2)pi (d)^2n=kJdiv sqrt (2)pi (d)^2p ,平均碰撞频率 =sqrt (2)pi (d)^2noverline (v)(其中d为分子的有效直径)平均自由程公式正确,平均碰撞频率公式A不正确;平均自由程公式不正确,平均碰撞频率公B式正确;C两个都对,D两个都不对

sqrt (2)pi :2 C. sqrt (2)pi :4 D. sqrt (2)pi :8

sqrt (2)pi -|||-C. dfrac (sqrt {2pi )}(4)-|||-D. dfrac (sqrt {2pi )}(8)

[ 0,dfrac (pi )(2)] D. [ -sqrt (dfrac {pi )(2)},0]

(int )_(-pi )^pi sqrt ({pi )^2-(x)^2}dx= )(int )_(-pi )^pi sqrt ({pi )^2-(x)^2}d

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

dfrac (2pi )(sqrt {3)} D. dfrac (pi )(6)

dfrac (2pi )(sqrt {3)}-|||-D. dfrac (pi )(6)

(B) (mu ,dfrac (1)(sqrt {2pi )})-|||-(C) (mu ,dfrac (1)(2)), (D)(0,σ).

10、曲面 =sqrt ({x)^2+(y)^2} 被 ^2+(y)^2=1 所截部分的-|||-面积为 () .-|||-(A)π;(B) √2π; (C)2

sqrt (2)BIa-|||-C. dfrac (pi )(2)BIa-|||-D.BIa