A) If electrons are ejected from the metal plate on the left side (called cathod
ID: 1499882 • Letter: A
Question
A) If electrons are ejected from the metal plate on the left side (called cathode), when they move to the right plate (anode), will they speed up or slow down?
B) If the voltage V in the diagram is increased, will the current detected by the picoammeter (pA) increase or decrease?
C) What is the “stopping voltage”? How is it determined in the experiment?
D) ) What is the relationship between the “stopping voltage” and the maximum kinetic energy of the ejected electrons?
E) If electrons are ejected from the cathode after receiving energies from the light beam shining on the cathode, how is the “stopping voltage” related to the wavelength of the light beam and the work function of the cathode?
F) The work function of a metal is given as 1.5 eV. Determine the stopping voltage, Vo, if the wavelength of light is 546 nm.
AnodeExplanation / Answer
A) slowdown
B) decreases
C) The minimum voltage in the ckt, to get zero photo current.
D) e*Vo = KE_max
E) eVo = (E_photon - Wo)
= (h*c/lamda - Wo) (here lamda is the waveength and Wo is wotk function)
F) Vo = (h*c/lamda - Wo)/e
= (6.626*10^-34*3*10^8/(546*10^-9) - 1.5*1.6*10^-19)/(1.6*10^-19)
= 0.775 Volts