The correct answer is: D. charge
Charge is the total deficiency or excess of electrons in a body. It is measured in coulombs (C). A positive charge indicates an excess of electrons, while a negative charge indicates a deficiency of electrons.
Current is the rate of flow of charge. It is measured in amperes (A). The current in a circuit is equal to the charge flowing through the circuit per unit time.
Voltage is the difference in electric potential between two points. It is measured in volts (V). The voltage in a circuit is equal to the work done per unit charge in moving a charge from one point to another.
Potential gradient is the rate of change of voltage with distance. It is measured in volts per meter (V/m). The potential gradient in a circuit is equal to the change in voltage divided by the change in distance.
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