Two resistors are made of the same material, one twice as long as the other. If the current through the shorter resistor is 5 A, what is the current through the longer resistor if they both have the same potential difference and cross-sectional area?

In a simple circuit with a fixed applied voltage $V$, how does increasing the resistance $R$ affect the electric current $I$ according to Ohm’s law?

In a DC circuit, which component opposes current flow?

In the context of resistors and Ohm's law, what SI unit is used to measure electrical resistance?

A wire runs from the positive plate of a capacitor, into lightbulb 1, then out from lightbulb 1 directly into lightbulb 2. When lightbulb 2 is connected to the negative plate of the capacitor, what is true about the charge moving through the two lightbulbs?

A copper wire with a radius of $2.0\mathrm{ mm}$ and a length of $0.80\mathrm{ m}$ is connected across the terminals of a $9.0\mathrm{V}$ battery. How much current flows in the wire?

A certain wire has length L and radius r, and a resistance of R. That wire is melted down and the same volume of the same metal is used to produce a wire with length 2L. What is the resistance of the resulting wire?

A copper wire and an aluminum wire have the same diameter. If the copper wire is $10\mathrm{ m}$long, how long is the aluminum wire if they have the same resistance?