• Tags: graphs, photoelectric, interpretation
• Difficulty: Moderate

Five key graphs in photoelectric effect:

1. Photocurrent (I) vs Collector potential (V): Starts at some value at V = -$V_{0}$ (zero current), increases with V, and saturates at large positive V. The saturation current depends on intensity. Different intensities give parallel curves with same -$V_{0}$ but different saturation currents.

2. $V_{0}$ vs Frequency (f): Straight line, slope = h/e, x-intercept = f_{0}. Most important graph for JEE.

3. KE_max vs Frequency: Straight line, slope = h, x-intercept = f_{0}, y-intercept = -φ.

4. Photocurrent vs Intensity: Linear (at fixed f > f_{0}).

5. $V_{0}$ vs Wavelength (λ): Hyperbolic curve ($V_{0}$ = hc/(eλ) - φ/e). Not a straight line.