26. Who discovered the concept of the photoelectric effect?
a) Albert Einstein
b) Isaac Newton
c) Galileo Galilei
d) James Clerk Maxwell
27. Who discovered the concept of the double-slit experiment?
a) Thomas Young
b) Isaac Newton
c) Galileo Galilei
d) James Clerk Maxwell
28. Who discovered the concept of radioactivity?
a) Marie Curie
b) Pierre Curie
c) Antoine Becquerel
d) Ernest Rutherford
29. Who discovered the neutron?
a) James Chadwick
b) Marie Curie
c) Pierre Curie
d) Antoine Becquerel
30. Who discovered the electron?
a) J.J. Thomson
b) Marie Curie
c) Pierre Curie
d) Antoine Becquerel