A photocathode having a work function of $2.4 \mathrm { eV }$ is illuminated with monochromatic light whose photon energy is $3.4 \mathrm { eV }$. What is maximum kinetic energy of the photoelectrons produced? $( c = 3.00$ $\times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } , h = 6.626 \times 10 ^ { - 34 } \mathrm {~J} \cdot \mathrm { s } , 1 \mathrm { eV } = 1.60 \times 10 ^ { - 19 } \mathrm {~J}$ )
A) $1.6 \times 10 ^ { - 19 } \mathrm {~J}$
B) $4.9 \times 10 ^ { - 19 } \mathrm {~J}$
C) $4.4 \times 10 ^ { - 19 } \mathrm {~J}$
D) $5.4 \times 10 ^ { - 19 } \mathrm {~J}$
E) $3.8 \times 10 ^ { - 19 } \mathrm {~J}$

Question

Quizplus · Accepted Answer

The maximum kinetic energy of the photoelectrons is given by the difference between the photon energy and the work function: $3.4 \, \mathrm{eV} - 2.4 \, \mathrm{eV} = 1.0 \, \mathrm{eV}$, which is equivalent to $1.0 \times 1.60 \times 10^{-19} \, \mathrm{J} = 1.6 \times 10^{-19} \, \mathrm{J}$.

A Photocathode Having a Work Function Of 2.4eV2.4 \mathrm { eV }2.4eV

A Photocathode Having a Work Function Of $2.4 \mathrm { eV }$