f=4.5×10 2MHz=4.5×10 8Hz
根据c=λf得λ=
c
f =
3×10 8 m/s
4.5×10 8 Hz ≈0.67m;
3km=3000m
根据v=
s
t 得t=
s
v =
3000m
3×10 8 m/s =1×10 -5s.
故答案为:0.67m,1×10 -5s.
f=4.5×10 2MHz=4.5×10 8Hz
根据c=λf得λ=
c
f =
3×10 8 m/s
4.5×10 8 Hz ≈0.67m;
3km=3000m
根据v=
s
t 得t=
s
v =
3000m
3×10 8 m/s =1×10 -5s.
故答案为:0.67m,1×10 -5s.