A student investigates the relationship between the length lll of a resistance wire and its resistance RRR. The student measures a constant current in the circuit:
I=0.45 A I = 0.45\text{ A} I=0.45 AThe table below shows the student's measurements of length lll and potential difference VVV.
| l/cml / \text{cm}l/cm | V/VV / \text{V}V/V | R/ΩR / \OmegaR/Ω |
|---|---|---|
| 20.0 | 0.62 | (i) |
| 40.0 | 1.26 | (ii) |
| 60.0 | 1.85 | (iii) |
| 80.0 | 2.50 | (iv) |
| 100.0 | 3.12 | (v) |
Calculate the resistance RRR of each length of wire using the equation R=VIR = \frac{V}{I}R=IV. Write down the calculated values for (i) to (v) to two decimal places.
Select the statement that best describes the relationship between RRR and lll from the results:
Justify your choice by reference to your calculated values.
Use the values in the table to estimate the potential difference VeV_{\mathrm{e}}Ve across 50.0 cm50.0\text{ cm}50.0 cm of the resistance wire.
Calculate the resistance of 50.0 cm50.0\text{ cm}50.0 cm of the resistance wire using the equation:
R=VeI R = \frac{V_{\mathrm{e}}}{I} R=IVeState your answer to a suitable number of significant figures (2 or 3) and include the unit.
132 exam-style questions on CIE IGCSE Physics 4.2.4a Resistance. Each one has a worked solution and a mark scheme showing where the marks go.