1. Define physical quantities.
ANS: Quantities, which are measurable,
are called physical quantities.
2. Give some examples of
physical quantities.
ANS: Mass, Distance, Time,
Temperature are some examples of physical quantities.
3. What do you mean by the term
‘measurement’?
ANS: Measurement is basically a
process of comparison of some unknown quantity with some known fixed quantity.
4. To express the measurement in
a proper and complete way we need ____ things.
ANS: two
5. Name the things needed to
express the measurement in a proper and complete way.
ANS: The two things needed to express
the measurement in a proper and complete way are, number and unit.
6. Define the term ‘unit’.
ANS: Unit is a fixed known quantity in
terms of which other quantities may be expressed.
7. What do you mean by
Non-standard units?
ANS: The units which are not
internationally accepted and vary from person to person, place to place, are
called as non-standard units.
8. Give some examples of
Non-standard units.
ANS: Some examples of non-standard
units are, hand span, cubit, arm span, foot span and pace.
9. Define ‘hand span’.
ANS: Distance, from the tip of the
thumb to the tip of little finger, in a stretched hand, is called as hand span.
10. One hand span measures
approximately ______ inches.
ANS: 9 inches
11. Define a ‘cubit’.
ANS: The length of a forearm is
called as a cubit.
12. One cubit measures
approximately ______ inches.
ANS: 18 inches
13. Define ‘arm span’.
ANS: The length from one end of an
individual’s arms to the other when raised parallel to the ground at shoulder
height at a 900 angle, is called as arm span or wing span.
14. Define ‘foot span’.
ANS: The distance between the point
of the toe and the heel of the foot, is called as foot span.
15. Define the unit ‘pace’.
ANS: Pace is the distance covered in
either one normal walking step or in a double step returning to the same foot.
16. Why is a hand span/ cubit/ arm
span/ foot step or pace, not used as a standard unit of length?
ANS: Because they vary from person to
person and thus cannot give us correct measurement.
17. Define a ‘standard unit’.
ANS: A standard unit is an accepted
unit, of a given physical quantity, used by different people, all over the
world.
18. Give some examples of
standard units.
ANS: metre, second, kilogram are some
standard units.
19. What do you mean by SI units.
ANS: The standard set of units which
are used, accepted, all over the world, is known as the International System of
Units or simply the SI units.
20. What is the SI unit of
length?
ANS: The SI unit of length is metre.
It is denoted by ‘m’.
21. What is the SI unit of time?
ANS: The SI unit of time is second.
It is denoted by ‘s’.
22. What is the SI unit of mass?
ANS: The SI unit of mass is kilogram.
It is denoted as ‘kg’.
23. What is the SI unit of
temperature?
ANS: The SI unit of temperature is
Kelvin. It is written as ‘K’.
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