• # question_answer The de-Broglie wavelength associated with an electron accelerated through a potential difference V is $\lambda .$ What will be its wavelength when the accelerating potential increased to 4 V?

As $\lambda \propto (1/\sqrt{V}),$ hence on increasing accelerating potential from V to 4V, de-Broglie wavelength decreases from $\lambda$ to $\lambda /2.$