1. For a metal with specified work function Φ0= 3.1 eV subject to exposure of light with variouswavelengths and intensity of 8.01 W/m2 directed at the metal sphere with a radius of 5 cm
(A) The maximum wavelength required to stimulate the photoelectron emission is

= 350 nm, whichis the kind of ultra-violate (UV)
(B) Under the exposure of light withλ = 248 nm, the maximum energy of the photoelectrons emittedfrom the metal is 1.5 eV
(C) Under the exposure of light with λ  = 155 nm, the maximum energy of the photoelectrons emittedfrom the metal is 4.5 eV
(D) Under the condition that the exposure of light λ  = 248 nm and 0.25% of the incident photons createphotoelectrons, the number of emitted photoelectrons is

(E) The increase of exposure light intensity can increase the photoelectrons numbers and energy