# Electric Circuits - Mission EC4 Detailed Help A certain electrical circuit contains a battery, wires and a light bulb. Which of the following would cause the bulb to shine less brightly? List all that apply ... . When a single light bulb is connected to a battery, the brightness of the bulb is dependent upon the amount of current in the circuit. Any variable that would affect the current would affect the bulb brightness in the same manner. Refer to the Formula Frenzy and Math Magic sections to determine how voltage and resistance affect the current. The current (I) in a circuit is dependent upon the electric potential difference (i.e., voltage or ∆V) impressed across the circuit and the overall resistance (R) of the circuit. The equation that expresses this relationship is:    I = ∆V / R. Equations serve as useful guides to thinking about how an alteration in one variable would affect another variable. An inspection of the current equation in the Formula Frenzy section reveals the dependency of current on voltage and resistance. The equation would suggest that an increase in the voltage drop across a circuit would increase the current. It also suggests that an increase in the resistance of a circuit would decrease the current.  