Question

Blue light can cause photoelectric emission from a metal, but yellow light cannot. If red light is incident on the metal, then

• A. photoelectric current will increase
• B. rate of emission of photoelectrons will decrease
• C. no photoelectric emission will occur
• D. energy of the photoelectrons will increase.

Answer 1

Answer: (C)

Threshold wave length is less than that of yellow light. So, the red light cannot cause photoelectric emission .