Answer:
Easy.
The energy of the emitted photoelectrons can be determined using the concept of the photoelectric effect. According to the photoelectric effect, the energy of the emitted photoelectrons is equal to the difference between the energy of the incident photons and the work function of the material.
In this case, we are given that the incident photons have an energy of 10 electron volts (eV). Let's assume the work function of the material is represented by W (in eV).
The energy of the emitted photoelectrons (Ee) can be calculated as:
Ee = incident photon energy - work function
Ee = 10 eV - W
We are also given that when photons with an energy of 5 eV strike the same surface, the emitted photoelectrons have an energy of 2 eV. Using this information, we can set up another equation:
2 eV = 5 eV - W
Solving this equation for W, the work function:
W = 5 eV - 2 eV
W = 3 eV
Now, we can substitute the value of the work function into the equation for the energy of the emitted photoelectrons:
Ee = 10 eV - W
Ee = 10 eV - 3 eV
Ee = 7 eV
Therefore, when photons with 10 electron volts of energy strike the photoemissive surface, the energy of the emitted photoelectrons will be 7 electron volts.