Hi There, Right I recently did an experiment in Physics to find out the internal resistance of a lemon when used as a power supply. We connected the lemon to a voltmeter, ammeter and variable resistor, changed the resistance on the variable resistance and measured the voltage and current against each other. So i have a table of voltage against current. I have drawn a graph of voltage against current, voltage on y axis, and current on the x axis. And drawn a line of best fit. Voltage is in milli volts, 10^-3 and current is in micro volts 10^-6 How would i go about finding the EMF and eventually the Internal resistance of the lemon when used as a power supply. Also how would i go about finding the intercept of the graph if the line of best fit does not go through the y axis on the scale i have used. Anything to help would be fantastic Thank you in advance.