Because of the internal resistance of a real battery, we know that the potential difference between the terminals 1. decreases as more current is drawn.
2. increases as more current is drawn.
3. is greater than the emf of the battery
4. increases as the internal resistance increases.

Aprotein molecule in an electrophoresis gel has a negative charge. the exact charge depends on the ph of the solution, but 30 excess electrons is typical. what is the magnitude of the electric force on a protein with this charge in a 1600n/c electric field? write in two significant numbers, and also in newton