In a photoelectric experiment light of wavelength 800 nm produces photoelectrons with the smallest de-Broglie wavelength of 1 nm . Light of 400 nm produces photoelectrons with smallest de-Broglie wavelength of 0.5 nm. Then the work function of the metal used in the experiment is nearly.

The metal which has the highest work function in the following is

If a photocell is illuminated with a radiation of 1240 $$\mathop A\limits^o $$, the stopping potential is found to be 8V. Then, the work-function of the emitter and the threshold wavelength are

The graph between the maximum speed $$(v_{max})$$ of a photoelectron and frequency $$(\nu)$$ of the incident radiation, in photoelectric effect is correctly represented by