In an electron microscope, the resolution that can be achieved is of the order of the wavelength of electrons used. To resolve a width of `7.5 xx 10^(-12)` m, the minimum electron energy required is close to :

Options

A. 1 keV
B. 25 keV
C. 500 keV
D. 100 keV

Answer

B

Explanation

`lamda=h/(mV)=h/(sqrt(2mE))=(12.27)/(sqrtV)A^(@)rArr0.075=(12.27)/(sqrtV)rArrsqrtV=12270/75rArrV=(164)^(2)=26896=26kV`
`thereforeEto25keV`