The energy that should be added to an electron, to reduce its de-Broglie wavelengths from `10^(-10) m` to `0.5 xx 10^(-10)` m wil be

Options

A. Four times the initial energy
B. Thrice the initial energy
C. Equal to the initial energy
D. Twice the initial energy

Explanation

`lambda=(h)/(sqrt(2mE))rArrprop(1)/(sqrt(E))rArr(lambda_(1))/(lambda_(2))=sqrt(E_(2)/(E_(1))rArr=4E_(1)`
`rArr(10^(-10))/(0.5xx10^(-10))=sqrt((E_(2))/(E_(1)))rArrE_(2)=4E_(1)`
Hence added energy `=E_(2) - E_(1) = 3E_(1)`