When a television set is displaying the image of a red wall, so that the entire screen appears red,
A)	the electrons inside the picture tube are only striking those screen phosphors that emit red light.
B)	the electrons inside have relatively low energies so that the screen phosphors glow with red heat.
C)	the electrons inside have relatively high energies so that the screen phosphors glow with red heat.
D)	only the red lamp inside the picture tube is illuminated.
Answer:A
When a television set is displaying the image of a red wall, so that the entire screen appears red,
A)	the electrons inside the picture tube are only striking those screen phosphors that emit red light. B)	the electrons inside have relatively low energies so that the screen phosphors glow with red heat. C)	the electrons inside have relatively high energies so that the screen phosphors glow with red heat. D)	only the red lamp inside the picture tube is illuminated.