Wenn sich die Wellenlänge \(\lambda\) um \(\diff \lambda\) ändert, wie groß ist dann die Änderung der Wellenzahl \(\diff \tilde{\nu}\)?
(A)\(\diff \tilde{\nu} = - \frac{\diff \lambda}{\lambda^2}\) (B)\(\diff \tilde{\nu} = -\;\diff \lambda \cdot {\lambda^2}\) (C)\(\diff \tilde{\nu} = -\;\diff \lambda \) (D)\(\diff \tilde{\nu} = - \frac{\diff \lambda}{\lambda}\)
