A 4 5 m length of copper wire at 20 C has a 3 m long section

Last updated: 6/10/2023

A 4 5 m length of copper wire at 20 C has a 3 m long section with diameter 2 2 mm and a 1 5 m long section with diameter 0 8 mm There is a current of 2 3 mA in the 2 2 mm diameter section Resistivity of copper at 20 C is given to be p 1 72x 10 70m a What is the current in mA in the 0 8 mm diameter section b What is the magnitude of the electric field E in V m in the 2 2 mm diameter section c What is the potential difference in V between the ends of the 4 5 m length of wire