When the voltage applied to an X-ray tube is increased from `V_(1)=10 ` kV to `V_(2)=20` kV, the wavelength difference between limit of the continous X-ray spectrum increases by a factor 3 The atomic number of the element of which the tube anticathode is made will be (30-x), Find Value of x.

Options

A. 62
B. 56
C. 45
D. 29

Answer

D

Explanation

` lambda_(alpha)-lambda'_(m)=3(lambda_(alpha)-lambda_(m))`
`:. (12375)/(10.2 (Z-1)^(2))-(12375)/(20xx10^(3))=3[(12375)/(10.2(Z-1)^(2))-(12375)/(10xx10^(3))]`
Solving , we get =29