A student investigates circuits containing different combinations of resistors. Circuit A is shown in Fig. 3.1. Circuit A is not complete. Fig. 3.1 A student determines the resistance of $$\(R_{1}\)$$. He uses a variable resistor in circuit B to control the current and draws a graph of $$\(V\)$$ against $$\(I\)$$. (i) Draw the circuit symbol for a variable resistor. (ii) Briefly explain one advantage of using a variable resistor to control the current. . . N

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