91Ó°ÊÓ

What is the power of a \(1.00 \times 10^{2} \mathrm{MV}\) lightning bolt having a current of \(2.00 \times 10^{4} \mathrm{~A} ?\)

Explain the properties of myelinated nerves in terms of the insulating properties of myelin.

If two different wires having identical cross-sectional areas carry the same current, will the drift velocity be higher or lower in the better conductor? Explain in terms of the equation \(v_{\mathrm{d}}=\frac{I}{n q A}\), by considering how the density of charge carriers \(n\) relates to whether or not a material is a good conductor.

If aluminum and copper wires of the same length have the same resistance, which has the larger diameter? Why?

You are riding in a train, gazing into the distance through its window. As close objects streak by, you notice that the nearby fluorescent lights make dashed streaks. Explain.

What current flows through the bulb of a \(3.00-\mathrm{V}\) flashlight when its hot resistance is \(3.60 \Omega ?\)

Calculate the effective resistance of a pocket calculator that has a \(1.35-\mathrm{V}\) battery and through which \(0.200 \mathrm{~mA}\) flows.

Why are two conducting paths from a voltage source to an electrical device needed to operate the device?

What power is supplied to the starter motor of a large truck that draws \(250 \mathrm{~A}\) of current from a \(24.0 \mathrm{~V}\) battery hookup?

In cars, one battery terminal is connected to the metal body. How does this allow a single wire to supply current to electrical devices rather than two wires?