4.
a.
C.
e.
Answer the following questions:
What is meant by measurement?
b.
Define. Why is it necessary to have standard units of measurement?
What are the fundamental units used in Science?
d. What are SI units? Define derived units.
What precautions should be taken while buying something?
f. How is a metre related to kilometre?
g. Name three physical quantities whose units are used as basic units.
h. What unit of length should be used to express the distance between
Kathmandu and Pokhara? Suggest the way to measure the distance between
the Sun and the Earth?
Name the SI unit of time and define it.
i.
Blooming Science & Environment Book 6
15
Answers
Answer:
What is meant by measurement?
the action of measuring something or finding it's size
Why is it necessary to have standard units of measurement?
We need standard unit for measurement to make our judgement more reliable and accurate. For proper dealing, measurement should be same for everybody. Thus there should be uniformity in measurement. For the sake of uniformity we need a common set of units of measurement, which are called standard units
What are the fundamental units used in Science?
the meter (m), the kilogram (kg), the second (s), the kelvin (K), the ampere (A), the mole (mol), and the candela (cd).
What are SI units?
The International System of Units (abbreviated SI from systeme internationale, the French version of the name) is a scientific method of expressing the magnitudes or quantities of important natural phenomena. There are seven base units in the system, from which other units are derived.
Define derived units.
Derived units are units of measurement derived from the seven base units specified by the International System of Units.
What precautions should be taken while buying something?
Ensuring that the thing purchased is measured in the right unit.
How is a metre related to kilometre?
A kilometre is 1000 metres
Name three physical quantities whose units are used as basic units.
time (second)
length (metre)
mass (kilogram)
electric current (ampere)
thermodynamic temperature (kelvin)
amount of substance (mole)
luminous intensity (candela)
What unit of length should be used to express the distance between Kathmandu and Pokhara?
200.9 km
Suggest the ways to measure the distance between the Sun and the Earth
The distance between Earth and the sun is called an astronomical unit, which is used to measure distances throughout the solar system.
Name the SI unit of time and define it.
Second. The second is the base unit of time in the International System of Units, commonly understood and historically defined as ¹⁄₈₆₄₀₀ of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each