Practise IB Physics HL D.2.17 Electric field applications with questions interpreting electric-field graphs, potential changes and physical consequences.
Hydrogen atoms in an ultraviolet (UV) lamp make transitions from the first excited state to the ground state. Photons are emitted and are incident on a photoelectric surface as shown.
The electric potential of the photoelectric surface is 0 V . The variable voltage is adjusted so that the collecting plate is at -1.2 V .
On the diagram, draw and label the equipotential lines at -0.4 V and -0.8 V .