Photoelectric effect

Chemistry Level 2

A piece of chromium is exposed to a light with wavelength $2.50 \times 10^{-7} \text{ m}$ . Suppose that the work function of the chromium is $7.21 \times 10^{-19} \text{J}.$ Then what is the maximum kinetic energy of the emitted photoelectrons?

7.4 \times 10^{-19} \text{J}

6.4 \times 10^{-20} \text{J}

7.4 \times 10^{-20} \text{J}

6.8 \times 10^{-19} \text{J}

1 solution

Michael Fuller
Apr 23, 2015

Energy of a photon = Work function + Maximum kinetic energy $\frac { hc }{ \lambda } =\phi +{ KE }_{ max }\\ { KE }_{ max }=\frac { hc }{ \lambda } -\phi \\ { KE }_{ max }=\frac { 6.63\times { 10 }^{ -34 }\times 3\times { 10 }^{ 8 } }{ 2.50\times { 10 }^{ -7 } } -7.21\times { 10 }^{ -19 }\\ =\boxed { 7.4\times { 10 }^{ -20 }J } \\$

Photoelectric effect

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