Let us consider a metal with work function 4-64 eV- If this metal is irradiated with photons having energy 10-42 - 10-19 J then the wavelength associated with an ejected electron is x - 10-9 m- What is the nearest interger value of X -

The work function of the metal =hν_o=4.64× 1.6× 10^ 19 J=7.42× 10^ 19 J Again we know , hν = hν_o+KE or KE = hν hν_o ⇒ KE =10.42× 10^ 19 J 7.42× 10^ 19 J=3× 10^ ...

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Standard XII

Chemistry

Photoelectric Effect

Let us consid...

Question

Let us consider a metal with work function 4.64 eV. If this metal is irradiated with photons having energy $10.42 \times 10^{- 19} J$ then the wavelength associated with an ejected electron is $x \times 10^{- 9} m$ . What is the nearest interger value of $x$ ?

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Solution

The work function of the metal
$= h ν_{o} = 4.64 \times 1.6 \times 10^{- 19} J = 7.42 \times 10^{- 19} J$
Again we know ,
$h ν = h ν_{o} + K E$
or $K E = h ν - h ν_{o}$
$\Rightarrow K E = 10.42 \times 10^{- 19} J - 7.42 \times 10^{- 19} J = 3 \times 10^{- 19} J$

From the de-Broglie equation,
$λ = \frac{h}{m v}$
$m = 9.1 \times 10^{- 31} kg (electron)$
$= \frac{h}{\sqrt{2 m (K E)}} = \frac{6.62 \times 10^{- 34}}{\sqrt{2 \times 9.1 \times 10^{- 31} \times 3.0 \times 10^{- 19}}}$
$= 8.96 \times 10^{- 9} m$
Thus, $x = 9$

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Let us consider a metal with work function 4.64 eV. If this metal is irradiated with photons having energy 10.42×10−19 J then the wavelength associated with an ejected electron is x×10−9 m. What is the nearest interger value of x?

Let us consider a metal with work function 4.64 eV. If this metal is irradiated with photons having energy $10.42 \times 10^{- 19} J$ then the wavelength associated with an ejected electron is $x \times 10^{- 9} m$ . What is the nearest interger value of $x$ ?