When light from one source, X, strikes a metal, electrons are ejected. When light from another source, Y, strikes the same metal, electrons are not ejected.
Answer
A
Light from source X has a higher intensity than light from source Y.
B
Light from source X has a lower intensity than light from source Y.
C
Photons of light from source X carry more energy than photons of light from source Y.
D
Photons of light from source X carry less energy than photons of light from source Y.