Option 1: James Chadwick - Photoelectric

This option is incorrect. James Chadwick is not correctly matched with the physical phenomenon of photoelectric effect. The photoelectric effect is actually associated with Albert Einstein.

Option 2: Albert Einstein - Neutron

This option is incorrect. Albert Einstein is not correctly matched with the physical phenomenon of neutron. The discovery of the neutron is credited to James Chadwick.

Option 3: Marie Curie - Radium

This option is correct. Marie Curie is correctly matched with the physical phenomenon of radium. Marie Curie is renowned for her research on radioactivity, which led to the discovery of radium.

Option 4: 3 only

This option is the correct answer. Marie Curie is correctly matched with the discovery of radium, while the other two pairings in options 1 and 2 are incorrect.

In summary, the correct pair of physical phenomenon and discover is Marie Curie - Radium, corresponding to option 4.