Question

If a potential difference of 20,000 volts is applied across an X-ray tube, the cut-*** wavelength will be

(a) 6.21 x 10-10 m

(b) 6.21 x 10-11 m

(c) 6.21 x 10-12 m

(d) 3.1 x 10-11 m

Answer 1

Correct Answer is: (b) 6.21 x 10-11 m

Photon energy at cut-*** wavelength = 20,000 eV.

∴ λc = 1242 eV nm/20 X 103 eV = 6. 21 x 10-11 m.