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Here are some graphs for the potential difference (p.d.) of four electrical supplies - OCR Gateway - GCSE Physics - Question 6 - 2019 - Paper 1
Question 6
Here are some graphs for the potential difference (p.d.) of four electrical supplies. Which graph shows a direct voltage? A (p.d.) + tim... show full transcript
Worked Solution & Example Answer:Here are some graphs for the potential difference (p.d.) of four electrical supplies - OCR Gateway - GCSE Physics - Question 6 - 2019 - Paper 1
Step 1
Which graph shows a direct voltage?
Answer
To determine which graph represents a direct voltage, we must understand the characteristics of direct voltage (DC). In a DC circuit, the potential difference remains constant over time and does not alternate.
- Graph A shows a sinusoidal waveform, indicating alternating current (AC).
- Graph B appears to fluctuate over time, which also indicates AC.
- Graph C maintains a steady potential difference; however, the line is shown dipping below zero, suggesting it is not pure DC.
- Graph D shows a rapid switch between two constant levels, both above and below zero, indicating a form of pulsed DC.
Hence, the graph that most closely resembles direct voltage is Graph C, as it displays the most constant behavior without oscillation, but technically, it does not qualify as 'pure' DC if it dips below zero. However, if we're strictly considering a stable constant level, it could be argued that both Graph C and Graph D represent variations of direct current. Therefore, Graph D should be noted for further clarification on specific circuit characteristics.