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Question: Answered & Verified by Expert
If the wavelength of an electromagnetic radiation is $2000 Å$, what is its energy in ergs?
ChemistryStructure of AtomTS EAMCETTS EAMCET 2003
Options:
  • A $9.94 \times 10^{-12}$
  • B $9.94 \times 10^{-19}$
  • C $4.97 \times 10^{-12}$
  • D $4.97 \times 10^{-19}$
Solution:
2917 Upvotes Verified Answer
The correct answer is: $9.94 \times 10^{-12}$
$E=h v, v=\frac{3 \times 10^{10}}{2000 \times 10^{-8}}=1.5 \times 10^{15} \sec ^{-1}$
$h=6.6 \times 10^{-27}$ erg sec
$E=h v=6.6 \times 10^{-27} \times 1.5 \times 10^{15}=9.94 \times 10^{-12} \mathrm{erg}$

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