Question 81: Dual Nature of Matter and Radiation

Question

The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of

Accepted Answer

For photo-electric effect, energy of the photon must be greater than the work function of the metal.
We know, $$E = {{1240} \over \lambda } = {{1240} \over {550}}$$ (as $\lambda=550$ nm given)
$\Rightarrow E=2.25$ eV
here, $$E > {\phi _{cs}}$$
So, $C_S$ only.

Answer

Both Cs and Li

Answer

Neither Cs nor Li

Answer

Li only

Answer

Cs only

Dual Nature of Matter and Radiation

The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of

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