The wavelength of matter wave is independent of

An electron accelerated by a P.D. of V volts possesses a de Broglie wavelength $\lambda$. If the accelerating potential is increased by a factor of $4$, the de Broglie wavelength of the electron will

The relativistic expression for the wavelength of electrons moving with very high speed is

The voltage applied across an $\mathrm{X}$-Ray tube is nearly,

The characteristic of the target element that determines the frequency of characteristic $\mathrm{X}$-Ray is

Ionisation in a gas cannot be produced by