Can someone please tell me how to solve this question:
The question in in the Edexcel AS student book page 126
In a resistance experiment, a gold ring was connected into a circuit as a resistor. The connection touched diametrically opposite points on the circular ring. Its diameter is 2 cm, and the metal's cross section is 3 mm by 0.5 mm. The voltemeter connected accross the ring measured 8.3 mV, whislt the current through it measured 18 A.
a) Calculate the resistivity of gold
b) Describe a practical difficulty in this experiment