A yellow coloured spectral line was observed at $$5890Ao$$ in the spectrum of a sodium vapour lamp. Calculate the minimum accelerating potential that is required to excite this line in an electron tube containing sodium vapour

Question

A yellow coloured spectral line was observed at $$5890Ao$$ in the spectrum of a sodium vapour lamp. Calculate the minimum accelerating potential that is required to excite this line in an electron tube containing sodium vapour

Infinity Learn · Accepted Answer

λ$$=5890$$×$$10$$−$$10m$$;$$c=3.0$$×$$108ms$$−We know that $$E=hv$$;$$E=hc$$λ$$E=6.626$$×$$10$$−$$34J$$.s×$$3.0$$×$$108ms$$−$$5890$$×$$10$$−$$10m=3.37$$×$$10$$−$$19JBut$$, $$1eV=1.6$$×$$10$$−$$19JHence$$, $$E=3.37$$×$$10$$−$$19J$$×$$1eV1.6$$×$$10$$−$$19J=2.1eV=$$ $$2.1$$ V x charge on one electron∴ $$2.1$$ Vis needed to accelerate the electron away from the atom.

Electromagnetic radiation and spectra

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A yellow coloured spectral line was observed at $5890 A^{o}$ in the spectrum of a sodium vapour lamp. Calculate the minimum accelerating potential that is required to excite this line in an electron tube containing sodium vapour

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Electromagnetic radiation and spectra

Remember concepts with our Masterclasses.

A yellow coloured spectral line was observed at 5890Ao in the spectrum of a sodium vapour lamp. Calculate the minimum accelerating potential that is required to excite this line in an electron tube containing sodium vapour

λ=5890×10−10m;c=3.0×108ms−We know that E=hv;E=hcλE=6.626×10−34J.s×3.0×108ms−5890×10−10m=3.37×10−19JBut, 1eV=1.6×10−19JHence, E=3.37×10−19J×1eV1.6×10−19J=2.1eV= 2.1 V x charge on one electron∴ 2.1 Vis needed to accelerate the electron away from the atom.

Ready to Test Your Skills?

free study material

A yellow coloured spectral line was observed at $5890 A^{o}$ in the spectrum of a sodium vapour lamp. Calculate the minimum accelerating potential that is required to excite this line in an electron tube containing sodium vapour