Physics - Modern Physics Question with Solution | TestHub

Characteristic frequencies are fixed by the target, so (A) is false; the electron rate is unchanged, so (B) is false. A higher $V$ can excite higher-series lines (K, then more), so the number of characteristic lines may increase, (C). ${\lambda }_0=hc/eV$ decreases with $V$ while ${\lambda }_{K\alpha }$ stays fixed, so the difference changes, (D).