Lifetimes of the molecules in the excited states are often measured by using pulsed radiation source of duration nearly in the nanosecond range. If the radiation source has the duration of 2 ns and the number of photons emitted during the pulse source is $$2.5\times 10^{15}\, J$$, calculate the energy of the source.

Asked by Abhisek | 1 year ago |  89

##### Solution :-

Frequency of radiation $$\nu$$

$$\nu =\dfrac{1}{2.0\times 10^{-9}s}\\ \\$$

$$\nu =5.0\times 10^{8}s^{-1}$$

Energy (E) of source = Nhν

Where,

N is the no. photons emitted

h is Planck’s constant

ν denotes the frequency of the radiation

Substituting these values in the expression for (E):

$$E= (2.5\times 10^{15})$$

$$(6.626\times 10^{-34}Js)(5.0\times 10^{8}s^{-1})\\ \\$$

$$E=8.282\times 10^{-10}J$$

Hence, the energy of the source (E) is $$8.282\times 10^{-10}J$$

Answered by Pragya Singh | 1 year ago

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