Electron is accelerated by 100 volt potential difference. Its wavelength will be comparable to that of :

Infrared radiator Microwave X-rays Radio waves

X-rays

The correct answer is option (3) : X-rays de-Broglie wavelength of electron =$\frac{1.227}{\sqrt{V}}nm$ $=\frac{1.227}{\sqrt{100}}$ $=0.1227\, nm$ Range of X-rays (0.01 - 10 ) nm