1. Figure 11.52 shows a Wheatstone-bridge circuit. The ratio arms P and Q can each be set at 10, 100, 1000 or 10 000 _ and the variable resistor R can be varied from 1 _ to 10 000 _ in steps of 1 _.
(a) Describe briefly how the bridge would be used to determine the value of the resistor, X .
(b) Suggest values of P, Q and R if the bridge is at balance and the resistor X is 2.864 _.
2. A slide-wire bridge has a wire 1mlong and is arranged as shown in Figure 11.26. What is the value of the unknown resistor when the value of the known resistor and the distance of the slider from the left-hand end of the wire for balance, are, respectively
(a) 10 _, 27 cm (b) 2 _, 68 cm (c) 60 _, 42 cm
