Final answer:
A single electron expelled due to a photon strike in a photoconductive cell can create a current, which is true. Voltage is not the same at every point in a given wire, which is false. Electric-field lines from a positive charge do spread out radially and point outward, which is true. Wave-particle duality does not exist for macroscopic objects, which is false.
Step-by-step explanation:
The statement that a current is created in a photoconductive cell even if only one electron is expelled from a photon strike is true. When a photon collides with a photoconductive material, it can transfer enough energy to an electron to free it from its atomic bond, creating an electron-hole pair. This free electron can then contribute to a current, even if it is just a single electron that has been released.
The concept of voltage in a circuit diagram is another interesting point. The statement that we can assume the voltage is the same at every point in a given wire within a circuit diagram is false. Voltage can vary between different points in a circuit, especially when there are components like resistors that cause voltage drops.
Regarding electric-field lines, the statement that electric-field lines from a positive point charge spread out radially and point outward is true. Electric field lines indicate the direction that a positive test charge would move if placed in the field.
Lastly, the concept of wave-particle duality is typically not observed on the macroscopic scale. This phenomenon is noticeable primarily at the quantum level, like with electrons or photons. Thus, the statement that wave-particle duality exists for objects on the macroscopic scale is false.