The circuit diagram shown in Fig includes a 6 V battery, an ammeter A, a fixed resistor `R_I` of 2` Omega ` and a resistance wire `R_2` connected between the terminals A and B. The resistance of the battery and ammeter may be neglected. Calculate the ammeter readings when the wire `R_2` is of
0.40 m length and of the same thickness and material as in case (a).

Explanation

On doubling the length (i.e., 0.40 m), the resistance of wire R2 is doubled, i.e., it becomes 8`Omega`
.` therefore `Total resistance `R_s = 2 + 8 = 10 Omega `
Current `I = (6)/(10) = 0.6 A`