David Sang and Darrell Hamilton Solutions for Chapter: Electrical Quantities, Exercise 2: Exercise 18.2

The equation $Q=It$ relates current, charge, and time. Complete the table to show the meaning of the symbols in this equation and give their units (name and symbol).

Write an equation linking the following units: coulomb, ampere and second.

A current of $2.4 \mathrm{A}$ flows in a circuit. State how much charge flows past a point in one second.

A current of $2.4 \mathrm{A}$ flows in a circuit. Calculate the charge that flows in $30 \mathrm{s}$.

An electric motor is supplied with current by a power supply. A charge of $720 C$ passes through the motor each minute. Calculate the current that is flowing.

A battery supplies a current of $1.25 \mathrm{A}$ to a circuit. Calculate how long it will take for $75 \mathrm{C}$ of charge to flow round the circuit.

A battery supplies a current of $1.25 \mathrm{A}$ to a circuit. If this battery has a capacity of $10 \mathrm{Ah}$, calculate how long can it supply this current.

During a journey in a car, the potential difference of $500 \mathrm{V}$ builds up, due to the static charge on the car caused by friction. A charge of $500 \mathrm{mC}$ is stored on the car. When the driver gets out and touches the car, this charge passes through the driver in $0.1 \mathrm{s}$. By calculating the current, explain why this $500 \mathrm{V}$ potential difference is not lethal(will cause death), but the mains potential difference is.