Calculate the velocity of ejected electron from the metal surface when light of frequency $2 imes 10^{15} \mathrm{~Hz}$ fall on the metal surface and the threshold frequency is $7 imes 10^{14} \mathrm{~Hz}$ for metal ?

Question

Calculate the velocity of ejected electron from the metal surface when light of frequency $2 	imes 10^{15} \mathrm{~Hz}$ fall on the metal surface and the threshold frequency is $7 	imes 10^{14} \mathrm{~Hz}$ for metal ?

Aicharya · Accepted Answer

$\frac{1}{2} m v^{2}=h v-h v_{0}$
$\Rightarrow \frac{1}{2} m v^{2}=h\left(v-v_{0}ight)$
$\Rightarrow \quad v=\sqrt{\frac{2 h}{m}\left(v-v_{0}ight)}$
$=\sqrt{\frac{2 \times 6.6 \times 10^{-34}}{9.1 \times 10^{-31}}\left(2 \times 10^{15}-7 \times 10^{14}ight)}$
$=1.37 \times 10^{6} \mathrm{~ms}^{1}$

Calculate the velocity of ejected electron from the metal surface when light of frequency $2 \times 10^{15}…

Solution