A monochromatic light beam is incident on the surface of a metal ...

[jparksx]

A monochromatic light beam is incident on the surface of a metal having a work function of 2.50 eV. If a 1.0-V stopping potential is required to make the electron current zero,
 
  what is the wavelength of light? (c = 3.00  108 m/s, h = 6.626  10-34 J  s, 1 eV = 1.60  10-19 J)
  A) 355 nm
  B) 423 nm
  C) 497 nm
  D) 744 nm

Question 2

When it is struck by 240-nm photons, a material having a work function of 2.60 eV emits electrons. What is the maximum kinetic energy of the emitted electrons?
 
  (c = 3.00  108 m/s, h = 6.626  10-34 J  s, 1 eV = 1.60  10-19 J)
  A) 2.58 eV
  B) 5.18 eV
  C) 2.00 eV
  D) 4.21 eV

[chereeb]

Answer to Question 1

A

Answer to Question 2

A