Question

a circuit contains two light bulbs connected in parallel. what would happen to the brightness of each light bulb if two more light bulbs were added in parallel to the first ones?
the brightness of each bulb would decrease because the total resistance of the circuit would decrease.
the brightness of each bulb would increase because the total resistance of the circuit would increase.
the brightness of each bulb would remain the same even though the total resistance of the circuit would decrease.
the brightness of each bulb would remain the same even though the total resistance of the circuit would increase.

Explanation:

In a parallel circuit, the voltage across each component (light bulb) is equal to the source voltage. When more bulbs are added in parallel, the total resistance of the circuit decreases (since \( \frac{1}{R_{total}}=\sum\frac{1}{R_i} \) for parallel resistors), but the voltage across each bulb remains the same. The brightness of a bulb depends on the power \( P = \frac{V^2}{R} \) (where \( V \) is voltage and \( R \) is bulb resistance). Since \( V \) and \( R \) for each bulb don't change, the power (and thus brightness) remains the same, even though total resistance decreases.

Answer:

The brightness of each bulb would remain the same even though the total resistance of the circuit would decrease.