一简谐波的频率ν=2000Hz,波长λ=0.20m,则该波的周期和波速为( )。
A.1/2000s,400m·s-1
B.1/2000s,40m·s-1
C.2000s,400m·s-1
D.1/2000s,20m·s-1
正确答案是A