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Question
Find the cutoff wavelength for the continuous X-rays coming from an X-ray tube operating at 30 kV.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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Solution
Given:
Voltage of the X-ray tube, V = 30 kV
Cutoff wavelength for continuous X-rays (λ) is given by
`λ = (hc)/(eV)`
Here ,
h = Planck's constant
V = Voltage of the X-ray tube
c = Speed of light
`therefore lambda = (1242 "eV"-"nm")/(e xx 30 xx 10^3)`
⇒ `lambda = 414 xx 10^-4 "nm" = 41.4 "pm"`
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