Electrons used in an electron microscope are accelerated by a voltage of `25 kV`. If the voltage is increased to `100 kV` then the de - Broglie wavelength associated with the electrons would

Options

A. increases by `2` times
B. decreases by `2` times
C. decreases by `4` times
D. increases by `4` times

Answer

b

Explanation

The de-Broglie wavelength `lambda` associated with the electron acceleration under a pot. Diff. `V` is,
`lambda=12.27/(sqrt(V))nm` or `lambda prop1/(sqrt(V))`
`:. (lambda_(1))/(lambda_(2))=sqrt((V_(2))/(V_(1)))=sqrt((100xx10^(3))/(25xx10^(3)V))=2` or `lambda_(2)=(lambda_(1))/2`