An X-ray tube is operated at 15 kV. Calculate the upper limit of the speed of the electrons striking the target.

Options

A. `7.26 xx 10^7 m//s`
B. `7.62 xx 10^7 m//s`
C. `7.62 xx 10^7 cm//s`
D. `7.26 xx 10^9 m//s`

Answer

A

Explanation

The maximum kinetic energy of an electron accelerated through a potential difference of V volt is `1/2 mv^2 = eV`
` therefore ` maximum velocity ` v = sqrt((2eV)/(m))`
` v = sqrt((2 x 1.6 xx 10^(-19) xx 15000)/(9.1 xx 10^(-31)) = 7.26 xx 10^7 m//s`