Question 241: 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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