Which of the following is maintained across the terminals of a battery?

a) a potential difference

b) a voltage drop

c) an electric charge

d) both a and b

Option D, both A and B

Explanation:

The potential difference is created across a battery (between its two terminal –one positive and the other one negative) when work is done to move a charge from one point to another. This potential difference is measured in volts. 1 volt is the potential difference between two points when one joule of potential energy is spent to move a charge of one coulomb from one point to the other.  

Voltage drop across a circuit is the amount of electric current lost due to resistance/ impedance with in the cables of the circuit.  

Hence, both potential difference and voltage drop occurs across the circuit,  

Option D is correct.

answer; hydrologic cycle;