b

5. ques.

18 kV accelerating voltage is applied across an X-ray tube. Calculate:
the velocity of the fastest electron striking the target,
the minimum wavelength in the continuous spectrum of X-rays produced.
(Mass of electron = 9 x 10exp-31 kg;
Charge on electron = 1.6 x 10exp-19 C;
h = 6.6 x 10exp-34 Js, c = 3 x 10exp8 m/s)

Solution
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V = 18 x 10exp3 V
me = 9 x 10exp-31 kg;
e = 1.6 x 10exp-19 C;
h = 6.6 x 10exp-34 Js,
c = 3 x 10exp8 m/s

v = 8 x 10exp7 m/s
.............................................(i)

min = 0.6875 x 10exp-10, 6.9 x 10exp-11m
.............................................(ii)

Ans: 8 x 10exp7 m/s; 6.9 x 10exp-11 m