[tex]dane:\\t = 2 \ min = 2\cdot60 \ s = 120 \ s\\n = 20\\v = 2\frac{m}{s}\\szukane:\\\lambda = ?\\\\Rozwiazanie\\\\\lambda = v\cdot T \ \ \rightarrow \ \ T = \frac{t}{n}\\\\\lambda = v\cdot\frac{t}{n}\\\\\lambda = 2\frac{m}{s}\cdot\frac{120 \ s}{20}\\\\\lambda = 12 \ m[/tex]
Odp. Długość tej fali λ = 12 m.
