Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100kV then the de–Broglie wavelength associated with the electrons would
Answer & explanation
Correct answer: option 2
$λ∝\frac{1}{\sqrt{V}}$
$⇒\frac{λ_1}{λ_2}=\sqrt{\frac{V_2}{V_1}}=\sqrt{\frac{100keV}{25keV}=2}⇒λ_2=\frac{λ_1}{2}$