Well, 3 questions actually. See below.
Please show me the working out and not just the answers.
Thanks in advance!
You are given the resistance, 30.9 Ohms of a 850 mm length of 0.122 mm diameter wire so:
when resistance is given in Ohms and length and diameter in mm.
Now you know you can use the first equation to find the resistence of any wire of the same material.