A solar cell generates a potential difference of 0.1055 V when a 500 resistor is

Question

A solar cell generates a potential difference of 0.1055 V when a 500 resistor is connected across it, and a potential difference of 0.1547 V when a 1000 resistor is substituted.  

a) What is the internal resistance of the solar cell?

b) What is the emf of the solar cell?

c) The area of the cell is 5.0 cm2, and the rate per unit area at which it receives energy from light is 2.0m W/ cm2. What is the efficiency of the cell for converting the light energy to thermal energy in the 1000 external resistor? (percent = no unit)

Please type calculations instead of uploading a photo.

Explanation / Answer

i_500 = current through 500 ohm resistor = 0.1055/500 = 2.11 x 10^-4 A

i_1000 = current through 1000 ohm resistor = 0.1547 / 1000 = 1.547 x 10^-4 A

voltage loop equation for each load resistance

e - i_500 * r - i_500*500 = 0

e - i_1000 *r - i_1000*1000 = 0

by solving these equation

(i_1000 - i_500 ) *r + i_1000 * 1000 - i_500 * 500 = 0

r = (i_500 * 500 - i_1000*1000 )/ ( 1_1000 - i_500)

r = 873.89 ohms

part b )

e - i_1000 *r - i_1000*1000 = 0

put the value of r

e = i_1000 *873.89 + i_1000*1000

e = 0.2899 = 0.29 V

part c )

n = Pused / Preceived

Preceived = IA = 2 x 10^-3 W/cm^2 * 5 cm^2 = 10 x 10^-3 W

n = (i_1000)^2*1000 / 10 x 10^-3

n = 0.239 % = 0.24 %

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