a circuit contains two light bulbs connected in parallel. what would happen to the brightness of each light…

Answer:

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

Explanation:

Step1: Understand parallel - circuit voltage

In a parallel - connected circuit, the voltage across each component is the same. Let the voltage of the power source be $V$. For each light - bulb, the voltage across it is always $V$ regardless of the number of bulbs added in parallel.

Step2: Analyze power formula

The power dissipated in a light - bulb is given by $P=\frac{V^{2}}{R}$, where $V$ is the voltage across the bulb and $R$ is the resistance of the bulb. Since the resistance of each individual bulb $R$ remains constant and the voltage $V$ across each bulb remains constant (because of the parallel - circuit property), the power $P$ of each bulb remains the same.

Step3: Relate power and brightness

The brightness of a light - bulb is directly related to the power dissipated in it. Since the power of each bulb remains the same, the brightness of each bulb remains the same.

Step4: Consider total resistance

The formula for the total resistance $R_{total}$ of a parallel circuit with resistors $R_1,R_2,\cdots,R_n$ is $\frac{1}{R_{total}}=\sum_{i = 1}^{n}\frac{1}{R_i}$. When more bulbs (resistors) are added in parallel, the total resistance $R_{total}$ of the circuit decreases. But this does not affect the voltage and power of each individual bulb.