Home
Class 12
PHYSICS
A cobalt target (Z = 27) is bomberded wi...

A cobalt target `(Z = 27)` is bomberded with electron and the wavelength of its characteristic spectrum are measured . A second , fainter characcteristic spectrum is also found because of an impurity in the target. The wevelength of the `K_(alpha)` lines are 178.9 pm (cobalt) and `143.5 pm` (impurity). What is the impurity?

Text Solution

Verified by Experts

Using Moseley's law and putting `c//lambda` for `v` (and assuming `b = 1`), we obtain
`sqrt (c )/(lambda_(Co)) = a Z_(Co) = a and sqrt (c )/(lambda_(x) = a Z_(x) - a`
Driving yields `sqrt(lambda_(Co))/(lambda_(x)) = (Z_(x) - 1)/(Z_(C o) - 1)`
Solving for the unknown , we find `Z_(x) = 30.0`, the impurty is zine.
Promotional Banner

Topper's Solved these Questions

  • ATOMIC PHYSICS

    CENGAGE PHYSICS|Exercise Solved Examples|23 Videos

  • ATOMIC PHYSICS

    CENGAGE PHYSICS|Exercise Exercise 4.1|15 Videos

  • ALTERNATING CURRENT

    CENGAGE PHYSICS|Exercise QUESTION BANK|65 Videos

  • ATOMS

    CENGAGE PHYSICS|Exercise QUESTION BANK|40 Videos

Similar Questions

Explore conceptually related problems

A cobalt (atomic no. =27 ) target is bombereded with electrons and the wavelength of its characteristic x -rays spectrum are measured. A seconf weak characteristic spectrum is also found due to an impurity in the target. The wavelength of the K_(alpha) lines 225.0pm (cobalt ) and 100.0pm (impurity). Atomic number of the impurity is (take b=1)

An X-ray tube with a copper target is found to be emiting lines other than those due to copper. The K_(alpha) line of coper is known to have a wavelength 1.5405 Å and the other two K_(alpha) lines observed have wavelengths 0.7090 Å and 1.6578 Å Identify the impurities.

In a coolidge tube, the tungsten (Z=74) target is bombarded by electrons. What is the minimum value of the accelerating potential to enable emission of characteristic K_(alpha) and K_(beta) lines of tungsten. ( The K,L & M levels of tungsten have Binding energies of 69.5, 11.3 & 2.30 keV respectively.)

The X-ray spectrum of a metallic target has been shown in figure (a) What is the accelerating potential difference for bombarding electrons? (b) Two characteristic X-rays have been shown in the figure one of them is k_(alpha) X-ray and the other one is k_(beta) X-ray. What is wavelength of k_(alpha) X-ray? (c) Find the atomic number of the target atom.

The K_(alpha) X - rays arising from a cobalt (z = 27) target have a wavelength of 179 pm . The K_(alpha) X - rays arising from a nickel target (z = 28) is

a. X-ray are electromagnetic waves because these are producted by the deceleration of fast moving electron . b. X-ray are electromagnetic waves because these produce line spectrum. c. the cut-off wavelength depends on the target metarial . d. The intensity of K_(alpha) transition is more probable then of K_(beta) e The transition. e. Frequency of K_(alpha) radiation is more than that of K_(beta) .

X-ray emitted from a copper target and a molybdenum target are found to contains a line of wavelength 22.85 n m attributed to the K_(alpha) line of an impurity element . The K_(alpha) line of copper (Z = 29) and molybdenum (Z = 42) have wavelength 15.42 nm and 7.12 nm , respectively. The atomic number of the impurity element is