Chemistry Class 11 NCERT Solutions: Chapter 2 Structure of Atom Part 14

Q: 49. Lifetimes of the molecules in the excited states are often measured by using pulsed radiation source of duration nearly in the nano second range. If the radiation source has the duration of Equation ns and the number of photons emitted during the pulse source is Equation calculate the energy of the source.

Answer:

Frequency of radiation Equation

Equation

Equation

Energy (E) of source = Equation

Where,

N=number of photons emitted

h = Planck’s constant

Equation = frequency of radiation

Substituting the values in the given expression of (E):

Equation

Equation

Hence, the energy of the source (E) is Equation

Q: 50. The longest wavelength doublet absorption transition is observed at 589 and 589.6 nm. Calculate the frequency of each transition and energy difference between two excited states.

Answer:

For Equation

Frequency of transition Equation

Equation

Frequency of transition ( Equation ) = Equation

Similarly, for Equation

Frequency of transition Equation

Equation

Frequency of transition Equation

Energy difference Equation between excited states Equation

Where,

Equation

Equation

Equation

Equation

Equation

= Equation

Equation

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