Which of the following statements is (are) NOT true about the emission of the photoelectrons from metallic surfaces? i. all metallic surfaces emits the same...

Which of the following statements is (are) NOT true about the emission of the photoelectrons from metallic surfaces? i. all metallic surfaces emits the same number of photoelectrons in a given light ii. most metallic surfaces emit the same number of photoelectrons in visible and infra-red light iii. a metallic surface emits photoelectrons only if the frequency of the incident light is higher than its own characteristics threshold frequency