1. **Problem Statement:** We are exploring the photoelectric effect by testing different colors of light (red, orange, yellow, green) to see if electrons are ejected and their speeds. 2. **Photoelectric Effect Formula:** The kinetic energy of ejected electrons is given by: $$K.E. = hf - \phi$$ where $h$ is Planck's constant, $f$ is the frequency of the light, and $\phi$ is the work function of the metal. 3. **Important Rules:** - Electrons are ejected only if $hf > \phi$. - The speed of electrons depends on the kinetic energy: higher $K.E.$ means faster electrons. - Frequency $f$ increases from red to green light. 4. **Testing Colors:** - Red light: lower frequency, likely $hf < \phi$, so no electrons ejected. - Orange light: frequency slightly higher, may or may not eject electrons depending on $\phi$. - Yellow light: higher frequency, electrons likely ejected with medium speed. - Green light: highest frequency among these, electrons ejected with fast speed. 5. **Summary Table:** | Light Color | Electrons Ejected | Electron Speed | |-------------|-------------------|----------------| | Red | No | N/A | | Orange | Possibly Yes | Slow/Medium | | Yellow | Yes | Medium | | Green | Yes | Fast | This matches the photoelectric effect principle that higher frequency light ejects electrons with greater kinetic energy.