題組內容

 2. A light source emitting radiation at frequency 7.00 × 10¹⁴ Hz is incapable of ejecting photoelectrons from a certain metal. In an attempt to use this source to eject photoelectrons from the metal, the source is given a velocity toward the metal.

 (a) When the speed of the light source is equal to 0.280 c, photoelectrons just begin to be ejected from the metal. What is the work function of the metal?