Question 220: Dual Nature of Matter and Radiation

Question

Sodium and copper have work functions $2.3$ $eV$ and $4.5$ $eV$ respectively. Then the ratio of the wavelengths is nearest to

Accepted Answer

We know that work function is the energy required and energy $E = h\upsilon $
$	herefore$ ${{{E_{NA}}} \over {{E_{Cu}}}} = {{h{\upsilon _{Na}}} \over {h{\upsilon _{cu}}}} = {{{\lambda _{cu}}} \over {{\lambda _{Na}}}}$
$\left[ {\,\,} ight.$ as ${\,\,\,\upsilon  \propto {1 \over \lambda }}$ for light $\left. {\,\,} ight]$
$	herefore$ ${{{\lambda _{Na}}} \over {{\lambda _{Cu}}}} = {{{E_{Cu}}} \over {{E_{Na}}}} = {{4.5} \over {2.3}} \approx {2 \over 1}$

Answer

$1:2$

Answer

$4:1$

Answer

$2:1$

Answer

$1:4$

Dual Nature of Matter and Radiation

Sodium and copper have work functions 2.3 eV and 4.5 eV respectively. Then the ratio of the wavelengths is nearest to

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