Electric Circuits - Mission EC7 Detailed Help

A battery is connected to a 12-ohm resistor and a 6-ohm resistor as shown below. The voltage drop across the 12-ohm resistor is ____ that across the 6-ohm resistor.

Voltage Drops in a Series Circuit:
Electric charge encounters an energy gain as it passes through the battery. This energy boost means that it also encounters an increase in electric potential. The amount of electric potential difference between the two terminals of the battery is equal to the voltage rating on the battery. The gain in electric potential made in the battery is lost by the charge when making the loop around the external circuit. In series circuits, this loss occurs in a stepwise fashion as the charge passes through each resistor. The sum of the voltage drops across each resistor is equal to the voltage rating of the battery. The voltage drop (V) across an individual resistor within a series circuit can be determined from the resistance of the resistor (R) and the current (I) in the circuit. For example:
V1= I • R1        V2= I • R2

This question asks you to compare the voltage drop across a 12-ohm resistor to the drop across a 6-ohm resistor in a series circuit. The current through individual resistors in a series circuit is the same. As discussed in the Know the Law section, the voltage drop across a resistor is dependent upon the current and the resistance of the resistor. As such, a 12-ohm resistor with the same current will experience more voltage drop than a 6-ohm resistor. And because the voltage drop is directly proportional to the resistance, the voltage drop across the 12-ohm resistor will be two times the voltage drop of the 6-ohm resistor.


Tired of Ads?
Go ad-free for 1 year