Question

If the kinetic energy of a free electron doubles, its de-Broglie wavelength changes by the factor

(a) \(\frac{1}{2}\)

(b) 2

(c) \(\frac{1}{\sqrt2}\)

(d) √2

Answer 1

(c) \(\frac{1}{\sqrt2}\)

λ = \(\frac{h}{\sqrt{2mK}}\)

When kinetic energy is doubled, 

= \(\frac{1}{\sqrt2}\) λ