(a) Connect the circuit as shown in fig. 1 and set R1 to 250Ώ.
(b) Ask the supervisor to check the circuit.
(c) Close switch S.
(d) Vary R1 from 250 Ώ to 50 Ώ in steps of 50 Ώ.  For each setting of R1 record the reading I1 on the ammeter A1.
(e) Open switch S.
(f) Disconnect the unknown resistance, Rx from the circuit and connect   the O – 300mA ammeter, A2 as shown in fig. 2.







(g) Set R1 to 250Ώ.
(h) Close switch S
(i) Vary R1 from 250Ώ to 50Ώ in steps of 50Ώ.  For each setting of R1, record the reading I2 on the ammeter, A2.
(j) Calculate (I2-I1) and  (I1/(I1-I2) for each  Setting of R1        
(k) Tabulate your result as shown in Table 1.

R1Ώ	I1(A)	I2(A)	(I2-I1)(A)	I1      I2-I1
250
200
150
50

(l) Plot a graph of R1(Ώ) the y-axis against  I1           on the x-axis
                                                                                                                                           
                                                           I2-I1

(m)Determine the slope of the graph plotted in (l)