Fundamental and Derived units

Introduction to Physics

Fundamental and Derived unitsGrade 10

What is Physics

• A simple definition of physics is "the science of measurement"

• Physics explains how things work in nature.

What is measurement?

• Measurement is a description using numbers.

• measurement allows us to make a quantitative comparison between the laws of physics and the natural world.

• Measurement = number x unit

The Système International (SI) of units

• SI units are those of the Systeme International d’unites adopted in 1960.

• The SI system of units provides a worldwide standard of measurement.

Physical quantity

• Any measurable quantity is called a physical quantity.

• Physical quantity is of two types (Fundamental/base quantity and derived quantity

Fundamental/ base Quantities

It is a physical quantity that does not depend on other physical quantities. There are seven base units

Derived Quantities

It is a physical quantity which depend upon other physical quantities. Here are a few examples of derived units

Multiple Choice

Physical quantities derived from base quantities through multiplication, division or a combination of both operations are

• physical quantities

• base quantities

• derived quantities

• scalar quantities

Multiple Choice

What is the SI unit for length?

• cm

• m

• km

• mm

Multiple Choice

Physical quantities that cannot be derived from other physical quantities are

• base quantity

• derived quantity

• physical quantity

• scalar quantity

Multiple Choice

A quantity that can be measured is a

• base quantity

• physical quantity

• derived quantity

• scalar quantity

Multiple Choice

The base SI unit of time is

• hour

• minute

• second

• millisecond

Multiple Choice

Where did the metric system originate from?

• France

• England

• United States

• Africa

Multiple Choice

Which of the following pairs of physical quantity and SI unit is correct ?

• Mass - SI unit : Gram

• Time - SI unit : Hour

• Electric current - SI unit : Volt

• Temperature - SI unit : Kelvin

Multiple Choice

Density = mass /volume . What is the SI unit for density?

• gm^-2

• gm^-3

• kgm^-2

• kgm^-3

Multiple Choice

Which one of the following is the derived unit?

• speed

• length

• mass

• luminous intensity

Multiple Choice

What is the SI unit of Amount of substance

• metre

• candela

• newton

• mole

Multiple Choice

Which one of these options is NOT a derived quantity?

• Area

• Volume

• Density

• Temperature

Multiple Choice

Which of the following physical quantities is a derived quantity?

• Electric current
• Momentum
• Temperature
• Mass

Multiple Choice

How many basic units does the SI system have

• 4

• 5

• 7

• 10

Multiple Choice

S.I. means?

• System Internationale

• Secret Intelligence

• System Intruments

• International Secret

Multiple Choice

Physical Quantities consist of a _______ and its _______.

• numerical magntitude, SI Unit

• quantity, physical state

• Si unit, physical state

• physical state, physical characteristics

Multiple Choice

Physics is concerned with which of the following matters?

• applying physics prinicples

• describing the physical world

• making predictions about a broad range of phenomena

• all of the above