Key concepts of physics: SI units, prefixes and conversions: Practice Questions

A student converts a time interval of 2.5 hours into seconds. What is the correct value in standard form?

An experiment measures the thickness of a gold foil as \(0.000000540\text{ m}\). Which of the following correctly expresses this value in nanometres (\(\text{nm}\)) and to two significant figures?

A data transmission cable transfers information at a rate of \(1.2\text{ Gbps}\) (gigabits per second). How many bits of information are transferred in \(2.5\text{ hours}\)? Express your answer in standard form to 2 significant figures.

A power station has an output of \(2.4\text{ GW}\). Convert this power into \(\text{kW}\) and express the value in standard form.

The intensity of radiation from a source is \(5.8 \times 10^{-4}\text{ W/mm}^2\). Convert this intensity into the SI unit of \(\text{W/m}^2\) and express it in standard form.

State the SI unit for mass and time.

Using standard form, calculate the potential difference across a \(1.2\text{ M}\Omega\) resistor when a current of \(5.0\times 10^{-6}\text{ A}\) flows through it. Give your answer in volts.

Physical quantities are categorized as either scalars or vectors. Understanding these is fundamental to mechanics.

In physics, prefixes are used to denote multiples and sub-multiples of units.

(a) Complete the following unit conversions:
(i) \(5.6\text{ GHz} = \) _________ \(\text{Hz}\)
(ii) \(320\text{ nm} = \) _________ \(\text{m}\)

(b) A computer processor performs a single calculation in \(0.4\text{ nanoseconds}\). How many calculations can it perform in exactly one hour? Give your answer in standard form.