If the potential difference applied across x-ray tube is V volts, then approximately minimum wavelength of the emitted X-rays will be

Options

A. `1240 / V Å`
B. `12400 / V Å`
C. `1227 /sqrtV Å`
D. `2400/V Å`

Answer

B

Explanation

`lamda_("min") = (hC)/(eV) = (6.6xx10^(-34)xx3xx10^8)/(1.6xx10^(-19) V)`
`= (19.8)/(1.6V) xx10^(-7) = (12.375xx10^(-7))/(V)`
`therefore lamda_("min") = (12375xx10^(-10))/(V) = 12400 Å`