일반물리학 2 — Circuits: Problem 28

28 A solar cell generates a potential difference of 0.10 V when a 500 \(\Omega\) resistor is connected across it, and a potential difference of 0.15 V when a 1200 \(\Omega\) resistor is substituted. What are the (a) internal resistance and (b) emf of the solar cell? (c) The area of the cell is 5.0 cm\(^2\), and the rate per unit area at which it receives energy from light is 2.0 mW/cm\(^2\). What is the efficiency of the cell for converting light energy to thermal energy in the 1200 \(\Omega\) external resistor?