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Q.
The photoelectric threshold wavelength of a certain metal is $3000\mathring{A}$ . If the radiation of $2000\mathring{A}$ is incident on the metal.
Dual Nature of Radiation and Matter
Solution:
$W _{ o }=\frac{ hc }{\lambda_{ o }}$
Energy of the radiation of wavelength $2000 \mathring{A}$ is greater than the energy of $3000 \mathring{A}$ hence we know
$eV _{ o }=\frac{ hc }{\lambda}-\frac{ hc }{\lambda_{ o }}$
$\therefore $ electron will be emitted.