Chemistry Class 11 NCERT Solutions: Chapter 2 Structure of Atom Part 17 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q: 54. If the photon of the wavelength pm strikes an atom and one of its inner bound electrons is ejected out with a velocity of calculate the energy with which it is bound to the nucleus.


Energy of incident photon (E) is given by,

Energy of the electron ejected (K. E)

Hence, the energy with which the electron is bound to the nucleus can be obtained as:

Q: 55. Emission transitions in the paschen series end at orbit and start from orbit n and can be represented as

Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.


Wavelength of transition = 1285 nm




Hence, for the transition to be observed at 1285 nm, n = 5.

The spectrum lies in the infrared region.

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