Question

Two electric bulbs $A\left(40W\right)$ and $B\left(100W\right)$ are first connected in series and then in parallel across a given source. Which of the following statement is correct?

• A. $A$ will burn brighter in series and $B$ in parallel
• B. $B$ will burn brighter in series and $A$ in parallel
• C. Both will burn brighter in series
• D. Both will burn brighter in parallel

Answer 1

The correct option is D Both will burn brighter in parallel

We know that brightness in any bulb is directly proportional to current through bulb.

In series effective resistance increases and current decreases as current is inversely proportional to resitance

In parallel effective resistance decreases current increases.

So in parallel,both bulb will brighter