Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

The Electric Current in an X-ray Tube (From the Target to the Filament) Operating at 40 Kv is 10 Ma. Assume that on an Average, 1% of the Total Kinetic Energy of the Electron Hitting - Physics

Sum

The electric current in an X-ray tube (from the target to the filament) operating at 40 kV is 10 mA. Assume that on an average, 1% of the total kinetic energy of the electron hitting hte target are converted into X-rays.
(a) What is the total power emitted as X-rays and (b) how much heat is produced in the target every second?

Solution

Given :
V = 30 KV
i = 10mA

1% of TKE (total kinetic energy) = X-ray
i = ne

or  n = (10^-2)/(1.6 xx 10^-19)

= 0.625 xx 10^17 (number of electrons)

KE of one electron = eV

= 1.6 xx 10^-19 xx 40 xx 10^3

= 6.4 xx 10^-15  "J"

"T"_("KE") = 0.625 xx 6.4 xx 10^17 xx 10^-15

= 4 xx 10^2  "J"

(b) Heat produced in target per second = 400 − 4 = 396 J

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