Odpowiedź :
[tex]Dane:\\f = 680 \ Hz = 680 \frac{1}{s}\\v = 340\frac{m}{s}\\Szukane:\\\lambda=?\\\\\lambda = v\cdot T\\\\ale: \ \ T = \frac{1}{f}\\\\\lambda = \frac{v}{f}\\\\\lambda = \frac{340\frac{m}{s}}{680 \frac{1}{s}}\\\\\boxed{\lambda = 0,5 \ m}[/tex]