$$X-rays$$ emitted from a copper target and a molybdenum target are found to contain a line of wavelength $$22.85$$ nm attributed to the Kα line of an impurity element. The Kαlines of copper (Z$$ $$=$$ $$29) and molybdenum (Z$$ $$=$$ $$42) have wavelengths $$15.42$$ nm and $$7$$ $$.12$$ nm, respectively. The atomic number of the impurity element is

Question

$$X-rays$$ emitted from a copper target and a molybdenum target are found to contain a line of wavelength $$22.85$$ nm attributed to the Kα line of an impurity element. The Kαlines of copper (Z$$ $$=$$ $$29) and molybdenum (Z$$ $$=$$ $$42) have wavelengths $$15.42$$ nm and $$7$$ $$.12$$ nm, respectively. The atomic number of the impurity element is

Infinity Learn · Accepted Answer

Using Moseley's law, $$v1/2=a(z$$−$$b)c$$λ$$11/2=az1$$−b and cλ$$21/2=az2$$−bλ$$2$$λ$$112=az1$$−$$baz2$$−b⇒$$7.1215.4212=(29$$−$$b)(42$$−$$b)$$   (42$$−$$b)=1.47(29$$−$$b)⇒$$b=1.44$$λ$$1$$λ$$12=(z$$−$$1.44)z1$$−$$1.44$$ $$15.4222.8512(27.56)=z$$−$$1.44$$⇒$$z=24$$

Remember concepts with our Masterclasses.

Ready to Test Your Skills?

free study material