Question

Two light bulbs are being used in a lab experiment with a single battery. Bulb A has half the resistance as Bulb B. Which bulb is the dimmest in series? Which bulb is the brightest in parallel? Explain.

Answer 1

Answer and Explanation:

It is given that bulb A has the half the resistance as B

WHEN THEY ARE CONNECTED IN SERIES : In series circuit we know that current is same in the whole circuit

The power is given by $P=i^2R$ the expression it is clear that the bulb which has more resistance consume more power as current is same, and the bulb which consume more power will be brightest

It is given that resistance of bulb A is half the resistance of B So bulb A will be dimmest in this case

WHEN THEY ARE CONNECTED IN PARALLEL : In parallel circuit voltage is same across the circuit

The power is given by $P=\frac{V^2}{R}$ from the expression it is clear that the bulb which has least resistance will consume more power and so will be brightest

As the resistance of bulb A is less so it will be brightest in this case