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.

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.