# FUNDAMENTAL QUANTITIES AND UNITS

## FUNDAMENTAL QUANTITIES AND UNITS

1. Fundamental quantities: mass, length, time and electric charge
2. Simple measurement of current and temperature.

## CONCEPT OF FUNDAMENTAL QUANTITIES

Fundamental quantities are physical quantities whose dimensions and units are not usually derived from other physical quantities. Basically, there are three fundamental quantities in mechanics. They include:

• Mass
• Length and
1. i) Mass: This is a fundamental quantity with dimension ‘M’, usually written in capital letter. The S.I. unit of mass is kilogramme (kg). Mass can also be measured in gramme (g), tonne (t), etc.
2. ii) Length: This is another fundamental quantity with dimension ‘L’, written in capital letter. The S.I. unit of length is metre (m). Length can also be measured in kilometre (km), centimetre (cm), inches (inch), feet (ft), etc.

iii) Time: Time is a fundamental quantity with dimension ‘T’, also written in capital letter. The S.I. unit of time is second (s). Time can also be measured in minutes and hours.

The below table summarized the dimensions and units of the basic fundamental quantities.

 S/N Quantity Dimension S.I. Unit 1. Mass M Kilogramme (kg) 2. Length L Metre (m) 3. Time T Second (s)

Evaluation:

1. List the three basic fundamental quantities.
2. What are their dimensions and SI units?

## OTHER FUNDAMENTAL QUANTITIES

 S/N Quantity S.I. Unit 1. Temperature Kelvin (K) 2. Current Ampere (A) 3. Amount of substance Mole (mol) 4 Luminous intensity Candela (cd)

NB: The educator should carry out activities on simple measurement of current and temperature with the students.

Activity Work – Practical

1. Measuring the temperature of boiled water in a specific interval of time say, 2mins as it cools down.
2. Measuring the current value in a simple electric circuit.

ELECTRONICS