Question Video: Understanding the Role of a Cell in a Circuit | Nagwa Question Video: Understanding the Role of a Cell in a Circuit | Nagwa

Question Video: Understanding the Role of a Cell in a Circuit Science • Third Year of Preparatory School

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The diagram shows an electric circuit containing a cell and a bulb. Complete the following sentence: The ＿ create(s) a potential difference across the ＿.

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Video Transcript

The diagram shows an electric circuit containing a cell and a bulb. Complete the following sentence. The blank create, or creates, a potential difference across the blank. (A) Bulb, cell; (B) bulb, wires; (C) wires, bulb; (D) cell, bulb.

First, let’s review some basic components in electric circuits and their functions. In electrical circuits, the wires are represented by straight lines and connect all the components in the circuit. Wires are conductors that easily allow electric charges to travel through the circuit. A bulb, represented by a circle with a cross inside it, will emit light when electric charges flow through the bulb. A cell in an electric circuit does work on electric charges in the circuit while they move from the positive terminal of the cell to the negative terminal of the cell. When there is an electric potential difference across a component, this means that electric charges either gain or lose energy when they pass through the component. A component that creates a potential difference must increase the energy of electric charges that move through it.

Taking this into consideration, let’s determine which of the components shown is the component that creates an electric potential difference. The only one of these components capable of transferring energy to electric charges to increase their energy is the cell. We see then that the cell creates an electric potential difference. Option (D) is the only option that fills the first blank with the word “cell.” So, the other options must be incorrect. We should, however, check that option (D) is fully correct.

Option (D) states that the second blank is filled by the word “bulb.” This means that the bulb is a component of the circuit that has an electric potential difference created across it by the cell. When electric charges pass through the bulb, these electric charges decrease in energy. The energy lost by the electric charges is released as light. We see then that the correct answer is option (D). The cell creates a potential difference across the bulb.

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