Question

Two identical lightbulbs are connected in series to a single 9.0 V battery.

Choose the correct graph showing the potential as a function of distance through the circuit, starting withV = 0 V at the negative terminal of the battery.

Answer 1

Answer: C (Third graph)

Here, the potential is zero at the initial position and the bulbs are identical.

The potential across each is,

$$ \begin{aligned} V &=\frac{9}{2} \\ &=\mathbf{4 . 5} \mathbf{V} \end{aligned} $$

The potential after the first bulb is \(4.5 \mathrm{~V}\).

The potential after the second bulb is,

$$ \begin{aligned} V &=4.5+4.5 \\ &=9 \mathbf{V} \end{aligned} $$

Hence, third graph is the correct option.