Question

Which of the following graphs shows the variation of photoelectric current (I) with voltage (V) between the electrodes in a photo-electric cell?

• A.
  
• B.
  
• C.
  
• D.
  

Answer 1

The correct option is A


As the voltage increases initially, more number of electrons overcome the repulsion of space electrons; hence, the current increases. However, as the voltage is further increased, the repulsion effect of space charge is completely nullified, so the current remains constant. Moreover, beyond the stopping potential, no electrons are ejected and the photocurrent is zero. Hence, the correct choice is (a).