Question

In an electrical circuit, three incandescent bulbs A, B, and C of rating 40 W, 60 W, and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness?

• A. The brightness of all the bulbs will be the same
• B. The brightness of bulb A will be the maximum
• C. The brightness of bulb B will be more than that of A
• D. The brightness of bulb C will be less than that of B

Answer 1

The correct option is C

The brightness of bulb B will be more than that of A

Step1: Given data

Each bulb has a power of $P_a=40W,P_b=60W,and{P}_c=100W$ and is connected in parallel to an electrical supply.

Every electrical device will have rated or design values printed on it, such as watts and voltage. Let $PandV$ be the power and voltage ratings of a bulb, respectively. These values provide information regarding resistance and permissible current.

Step2: Formula for power

$P=V\times I=\frac{V^2}{R}[whereP=power,V=coltage,I=current,R=resis\tan ce]$

Step3: Analyzing the data

1. Because the three bulbs are linked in parallel, the voltage applied across them will be the same.
2. Let's call voltage $V$, and the current flowing through them will be different.
3. As the three bulbs expend various amounts of energy, the current traveling through them will vary as well, resulting in different brightness.
4. Demonstrating with the help of a diagram
5. We know that the bulb's brightness is proportional to the amount of power it consumes or the quantity of current it draws.

Step4: Understanding the brightness

We can see that $P_c>P_b>P_a$ from the information provided.

Bulb C has the most power, and its brightness is the highest of the three. Bulb A has the lowest brightness. As a result, bulb B is sandwiched between these two.

Therefore, the brightness of bulb B will be more than that of A.

Hence, option C is the correct answer.