A technician conducts an experiment to determine the electrical characteristics of a newly developed alloy wire, WWW.
The technician plots a graph of potential difference V V\,V on the vertical axis against current I I\,I on the horizontal axis.
Explain how this graph can show that the wire obeys Ohm's law.
At the highest current reading of 2.5 A, the plotted potential difference lies slightly above the expected straight line of best-fit. Suggest a physical reason for this observation.
State two ways the technician can check if their experimental results are reproducible.
The alloy wire has a resistance of 12.5 Ω.
Calculate the power dissipated by the wire when the current is 1.2 A.
Use the equation:
power=(current)2×resistance \text{power} = (\text{current})^2 \times \text{resistance} power=(current)2×resistance42 exam-style questions on OCR GCSE Physics Simple circuits. Each one has a worked solution and a mark scheme showing where the marks go.