- rate of photoelectron release is proportional to intensity of incident light
- shining light on a metal "bombards" it with photons
- no time delay
+- one photon releases one electron
#### Work function and threshold frequency
$\phi$ is work function ("latent" energy)
Gradient of a frequency-energy graph is equal to $h$
-y-intercept is equal to $\phi$
+y-intercept is equal to $\phi$
+voltage $V$ in circuit is indicative of max kinetic energy in eV
#### Stopping potential $V_0$
+
+Smallest voltage to achieve minimum current
+
$$V_0 = {E_{K \operatorname{max}} \over q_e} = {{hf - \phi} \over q_e}$$
## Wave-particle duality