Answer:
2.8 %
Step-by-step explanation:
Power deliver by the cell = 4.2 x 10^-3 W
Power given to the cell = 0.15 W
The efficiency of the cell is defined as the ratio of power deliver by the cell to the power given to the cell.
So, the efficiency of the cell
= power deliver by the cell / power given to the cell
=
![(4.2*10^(-3))/(0.15)](https://img.qammunity.org/2020/formulas/physics/college/f46wd1v5cc1kv5a1zelu1hqmsxxfmnaqp5.png)
= 0.028
in percentage form = 0.028 x 100 % = 2.8 %
Thus, the efficiency of the photo voltaic cell is 2.8 %.