I am helping a high school student with a physics experiment on internal resistance of a cell. My background is in chemistry, not physics.
Browsing SE for lab design, Measurement of internal resistance of a battery pops up. Now the high school lab cannot generate square waves so I was looking for alternatives.
I understand that in an open circuit, emf is the same as the voltage across the cell. The school does not have a potentiometer. There are videos such as this video at 4:20 that shows an open circuit, with an emf measurement. But wouldn't the cell form a circuit with the multimeter, thereby voiding the set up because the current is non-zero?
Please kindly point out what I am missing, and provide me with tips on how to avoid shorting the circuit and/or the multimeter. Thank you!