Resistance of a Wire

Resistance of a Wire: Practice Problems

A silver wire is 4.5 m long and 0.45 mm in diameter. What is its resistance?

The tungsten filament of a light bulb has a resistance of OLE-object If the filament is 27 cm long, what is its diameter?

A bird lands on a bare copper wire carrying a current of 32 A. The wire is 8 gauge, which means that its cross-sectional area is OLE-object (a) Find the difference in potential between the birds feet, assuming they are separated by a distance of 6.0 cm. (b) Will your answer to part (a) increase or decrease if the separation between the birds feet increases? Explain.

A current of 0.76 A flows through a copper wire 0.44 mm in diameter when it is connected to a potential difference of 15 V. How long is the wire?

What is the resistance per meter of an aluminum wire with a cross-sectional area of OLE-object (b) Would your answer to part (a) increase, decrease, or stay the same if the diameter of the wire were increased? Explain.

The interior of the human body has an electrical resistivity of OLE-object (a) Estimate the resistance for current flowing the length of your index finger. (For this calculation, ignore the much higher resistivity of your skin.) (b) Your muscles will contract when they carry a current greater than 15 mA. What voltage is required to produce this current through your finger?

Consider a rectangular block of metal of height A, width B, and length C, as shown in the figure below. If a potential difference V is maintained between the two OLE-object faces of the block, a current OLE-object is observed to flow. Find the current that flows if the same potential difference V is applied between the two OLE-object faces of the block. Give your answer in terms of OLE-object