[填空题]
The circuit shown is used to measure the variation of the resistance R of a wire with the length L of the wire. The wire is connected across points X and Y.
A voltmeter and an ammeter are connected to the circuit in order to investigate the relationship.
(1).Draw the ammeter and voltmeter on the given circuit with their correct connections.
(2).State the purpose of connecting a resistor in series with the wire as shown in the diagram.
2.The diameter d of the wire is kept constant at $d=0.58±0.01\,mm$. Determine the percentage uncertainty of the cross sectional area A of the wire.A=
3.The graph shows the variation of resistance of the wire R with the wire's length L.
(1).Draw the line of best fit.
(2).Use the graph to estimate the resistivity of the wire.ρ= $ \times10^{-6}Ωm$
