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EXERCISE
A. Objective Questions
1. Write TRUE or FALSE for each statement.
a) S.I unit of temperature is Fahrenheit. FALSE
b) Every measurement involves two things – a number and a
unit. TRUE
c) Mass is the measure of quantity of matter. TRUE
d) The S.I. unit of time is hour. FALSE
e) Area can be expressed as the product of lengths of two
sides. TRUE
2. Fill in the
blanks
a) The S.I. unit of length is metre,
of time is second, of mass is kilogram.
b) 0C is the unit
of temperature.
c) 1 metric tonne = 1000 kg.
d) The zero mark in Celsius
thermometer is the melting point of ice.
e) The thermometer used to
measure the human body temperature is called
the clinical
thermometer.
f) The normal temperature of
human body is 37 0C or 98.6 0F.
g) The mass of
an object is measured with the help of a beam balance.
Following steps to be followed while measuring the length of a pencil.
3. Match the following columns:
Column A Column B
a) Length of a housing plot i) Clock
b) Breadth of a book ii) Beam balance
c) Mass of an apple iii) Thermometer
d) Period of time for study iv) Measuring tape
e) Temperature of a body v) Graph paper
f) Surface area of leaf vi) Metre rule
Ans. a-(iv), b-(vi), c-(ii), d-(i), e-(iii),
f-(v)
4. Select the
correct alternative.
a) The symbol of degree Celsius is
(i) 0C
(ii) 0F (iii) K (iv) 0K
b) 10mm is equal to
(i)1 cm
(ii) 1 m (iii)10 dm (iv)10 cm
c) The amount of surface occupied by an object is called its
(i) volume (ii) area (iii)mass (iv) length
d) A metre ruler is graduated in
(i) m (ii) cm
(iii) mm (iv) km
e) A thermometer is graduated in
(i) Kelvin (ii) 0C (III) g (iv) cm
B. Short/Long answer
questions
1. What is
measurement? How is a
measurement expressed?
Measurement is a comparison of
an unknown quantity with a known
fixed quantity of same kind.
Measurement is expressed in numbers and unit.
If the unit is u and number is n
Then a measurement is expressed as:
Measurement = n x u = n u
2. State two characteristics of a unit.
The unit must have the following characteristics:
·
It
should be of convenient size.
·
It
must be universally accepted.
3. Name four basic measurements in our daily
life.
The four basic measurements in our daily life are (i) Length,
(ii) Mass,
(iii) Time and (iv) Temperature
4. What are the S.I. units of (i) mass (ii)
length (iii) time and (iv) temperature?
Write their symbols.
Quantity
|
S.I.Unit
|
Symbol for S.I. Unit
|
i) Mass
|
kilogram
|
kg
|
ii) Length
|
Metre
|
m
|
iii) Time
|
Second
|
s
|
iv) Temperature
|
kelvin
|
K
|
5. Define one metre, the S.I. unit of length.
State its one multiple and
one submultiple.
One metre is defined as the distance travelled by light in
air in
1/ 3 x 108 of a second. The multiple of metre is
kilometre and submultiple
of
metre is centimetre.
6. Convert the following
quantities as indicated.
a) 12 inch = 1 ft b) 1ft = 30.48
cm c) 20 cm = 0.2 m
d) 4.2 m = 420 cm e) 0.2 km = 200
m f) 0.2 cm = 2 mm
g) 1 yard = 0.91 m
7. a) Describe
in steps how would you measure the length of a pencil
using a metre
ruler. Draw a diagram if necessary.
Following steps to be followed while measuring the length of a pencil.
STEP 1 – Take a pencil AB and a meter ruler.
STEP 2 – Put the pencil near the ruler such that the Point A
of the
pencil
coincide with the 0 mark on the ruler.
STEP 3 – Keeping the eye at point P vertically above the
other end
B of the
pencil observe which point of the ruler coincides with
the point
B of the pencil.
STEP 4 – It will be observed that the point B is coincides at
6.5 mm of
the
ruler.
Conclusion: Hence it is concluded that the length of the pencil is 6.5
mm.
b) Explain with
an example how you will use the metre ruler in part (a)
if the ends of
the ruler are broken.
If the ends of the ruler are
broken, we will use the following steps to get the
correct measurement of the
pencil.
STEP 1 – Take a broken
ruler and a pencil AB to be measured.
STEP 2 – Place the pencil near the ruler so that, the point A
of the pencil
coincide with the ruler at reading 2 cm.
STEP 3 – Keeping the eye at point P vertically above the
other end
B of the
pencil observe which point of the ruler coincides with
the point B of the pencil.
STEP 4 – It will be observed that the point B of the pencil
coincides at
8.5 mm of
the ruler.
STEP 5 – Get the difference of these two reading, which is
the length of the
pencil.
Conclusion: Hence it is concluded that the length of the pencil is the
difference of reading taken at both the ends of the pencil.
in this case the length of the pencil is 8.5 mm – 2 mm = 6.5
mm
8. Name the device which you will use to
measure the perimeter of your
playground. Describe
in steps how you will use it.
We should use a measuring tape of length 100 m to measure the
perimeter of the playground.
We should follow the following
steps to measure the perimeter
of the playground ABCD
STEP 1 – Measure the length AB by coinciding the 0 point of
the measuring
tape at
point A, let it be P metre.
STEP 2 – Measure the length BC by coinciding the 0 point of
the measuring
tape at
point B, let it be Q metre.
STEP 3 - Measure the length CD by coinciding the 0 point of
the measuring
tape at
point C, let it be R metre.
STEP 4 - Measure the length DA by coinciding the 0 point of
the measuring
tape at point D, let it be Q metre.
STEP 5 – Add all the lengths P, Q R and S
Conclusion: Perimeter of the playground will be (P + Q + R + S) meter.
9. The diagram below shows a stick placed along
a meter ruler. The
length of the
stick is measured keeping the eye at positions A, B and C
(a) Write the length of the stick PQ as
observed for each position of the
eye. Are they all same?
Length of the stick observed from eye position A is 3.4 cm
Length of the stick observed from eye position B is 3.2 cm
Length of the stick observed from eye position C is 3.0 cm
They all are not same. They all are different
(b) Which is the correct position of the eye? Write the correct length of
the stick.
The correct position of eye is point B. The correct length of
the stick
is 3.2 cm
10. Define
mass. State its (i) S.I. (ii) C.G.S and (iii) F.P.S units. How they are
Related?
The mass of a body is the amount of matter contained in it.
The S.I unit of mass is kilogram (kg)
The C.G.S unit of mass is gram (g)
The F.P.S unit of mass is pound (lb)
1 kg = 1000g, 1 g = 10-3 kg, 1 lb = 453.59 g
11. Convert the
following quantities as indicated.
(a) 2500 kg = 2.5 metric
tonne
(b) 150 kg = 1.5 quintal
(c) 10 lb = 4.5359 kg
(d) 2500 g = 2.5 kg
(e) 0.01 kg = 10 g
(f) 5 mg = 5 x 10-6 kg
12. Name the
instrument which is commonly used to measure the mass of
a body. State
how it is used.
The most commonly used
instrument to measure mass is the beam
balance.
On holding the beam
balance first ensure that
there is nothing on the either
pan and the beam is
horizontal. The body whose
mass is to be measured is
placed on the left pan. The
standard weights are
placed on the right pan. It should be so adjusted that the
beam is
again horizontal on holding the balance up. The totals of the
weight
on the right pan gives the mass of the body placed on the
left pan
13. Define one kilogram, the S.I unit of mass.
How is it related to (i) quintal,
(ii) metric tonne and (iii) gram?
The mass of 1 litre of water at 40 C is considered
as 1 kilogram.
(i) 1 quintal = 100 kg
(ii) 1 metric tonne = 1000 kg
(iii) 1 kg = 1000 g or 1 gram = 10-3 kg
14. Name and
define the S.I unit of time. How is it related to (i) minute,
(ii) hour,
(iii) day and (iv) year?
The S.I unit of time is second. In short form it is written
by the letter s.
One second is defined as the time interval between two
consecutive
ticks that we hear from a pendulum wall clock.
(i) 1 minute = 60 s
(ii) 1 h = 60 minute = 3600 s
(iii) 1 day = 24 hour = 86400 s
(iv) 1 year = 365 days = 3.15 x 107 s
15. Name two devices used to measure the short
time interval of an event.
Two devices for measuring the short time interval are (i)
stop clock and
(ii) stop watch
16. Express in second. (i) 3 minute 15 second
and
(ii) 5 hour 2 minute 5 second
(i) 3 minute 15 second = (3 x 60) + 15 second = 180 + 15 =
195 second
(ii) 5 hour 2 minute 5 second = (5 x 3600) + (2 x 60) + 5
second
= 18000 + 120 + 5 = 18125
second
17. What does
the temperature measure?
Temperature measures the
degree of hotness or coldness of an object.
18. Name the
(i) S.I unit and (ii) one common unit of temperature. Write
their symbols
also.
(i) The S.I unit of temperature is kelvin and the symbol for
kelvin is K
(ii) Other common unit of temperature is degree celsius or
degree
centigrade and the symbol is 0C
19. Name the
instrument used for measuring the temperature of a person.
Draw its
labelled neat diagram.
A clinical thermometer is
used for measuring the temperature of a
person.
20. Write the
temperature of (i) melting ice (ii) boiling water
(i) Temperature for melting
ice 00 C
(ii) Temperature for boiling
water 1000C
21. What is a
clinical thermometer? State its
special features. Draw a
labelled neat
diagram of a clinical thermometer showing the range of
temperature
marked on it.
A clinical thermometer is
used for measuring the temperature of a
person.
A clinical thermometer has a marking from 350 C to
420 C. It has a kink
just above the bulb called constriction. This constriction
prevents the
mercury from falling back. The temperature of a healthy
person is
370 C. This temperature is marked by a red arrow.
= 300 cm2
22. What is the normal temperature of the human
body? How it is indicated
in a clinical thermometer?
The normal temperature of the human body is 370 C
or 98.60 F. In a
clinical thermometer it is indicated as a red arrow mark at
370 C in a 0 C
thermometer and at 98.60 F in a 0F
thermometer.
23. Can a
clinical thermometer be used to measure the temperature of
boiling water? Give reason for your answer.
A clinical thermometer cannot be used to measure the
temperature
of boiling water. Because it can measure only up to 420
C and the
water boils at 1000 C.
24. Explain the
term ‘area of a surface’.
The total surface occupied by an object is called its surface
area.
The surface area can be expressed in terms of the product of
two
measurements in length.
For example: To find the area of the base a book, we measure
its
length and breadth. If the length of the book is 20 cm and
its breadth
is 15 cm, then the area of the book is given as:
Area of the base of the book = length x breadth
= 20 cm x 15 cm
= 300 cm2
25. Name the
S.I unit of area and define it.
The S.I unit of area is square meter or meter2
which in
short form written as m2.
One square meter is defined as the area of a square of each side of 1 metre.
26. How are the
units (i) square yard (ii) hectare (iii) km2 (iv) cm2 (v)
mm2 related to the
S.I.unit of area?
The S.I unit of area is square meter or meter2
which in short form written
as m2
(i) 1 square yard = 1 yard x 1 yard = 0.9144 m x 0.9144 m =
0.8361 m2
(ii) 1 hectare = 100 metre x 100 metre = 10000 m2
(iii) 1 km2 = 1 km x 1km = 1000 metre x 1000 metre
= 106 m2
(iv) 1 cm2 = 1 cm x 1 cm = (1/100m) x (1/100m) =
1/10000 m2 = 10-4 m2
(v) 1 mm2 = 1 mm x 1 mm = (1/1000m) x (1/1000m) = 10-6 m2
27. Explain how
you will measure the area of (a) a square (b) a leaf.
(a) To measure the area of a square, first measure length one
side. Let
it be a . Then the area of
the square = side x side = a x a = a2
(b) To measure the area of a leaf, place it on a graph paper.
Draw the
outline of the leaf and remove it from the paper. Count the
number
of complete squares and the number of incomplete squares
which
are half more than half of a complete square within the line.
Ignore
the squares which are less than half.
The approximate area of the leaf = (No. of complete squares +
No.
of half or more than half of complete squares) x Area of one
square.
*************************************************
Extra
Questions and Answers
A. Objective Questions
1. Fill in the
blanks
(a) Physics is a science of measurement.
(b) Measurement is
the basic process of comparison of the given
quantity with a standard unit.
(c) The distance between two fixed point is called length.
(d) The F.P.S unit of length is foot.
(e) The F.P.S unit of mass is pound.
(f) The interval between two instances or events is called time.
(g) The C.G.S and F.P.S unit of time is second.
(h) The S.I unit of temperature is kelvin.
(i) The common units of temperature are degree celsius and degree
fahrenheit.
(j) Doctors use a clinical
thermometer to measure a
patient’s body
temperature.
(k) The total surface occupied by an object is called its area.
(l) The S.I unit of area is square
metre (m2).
(m) The value obtained on measuring a quantity is called its magnitude.
(n) Symbols for a unit named after a scientist is always
written in
capital letter.
(o) Symbols used for a unit other than the names of scientists
is always
written in small letter .
(p) In C.G.S system the unit of length is centimetre (cm).
(q) Vernier callipers can measure a length less than 1 mm.
(r) To measure the length up to 0.1 mm Vernier calliper is
used.
(s) To measure the length up to 0.01 mm Screw gauge is
used.
(t) To measure the length of a curved line you will use a measuring tape.
(u) A measuring tape is a flexible ruler.
(v) A goldsmith uses physical
balance.
(w) Normal temperature of human body is 370 C or 98.60 F.
2. Select the
correct alternative.
a) The unit of current is.
(i) kilogram (ii) pound (iii)
ampere (iv) second
b) The thickness of a coin is expressed in
(i) cm (ii) mm
(iii) m (iv) km
c) A metre ruler can measure a length up to
(i) 1 mm (ii) 1 cm (iii) 10 mm (iv) 0.1 mm
d) Which of these is not an available length of measuring
tape?
(i) 1 m (ii)
10 m (iii) 100 m (iv) 75 m
e) An electronic stop watch
cam measure time intervals accurately
up to
(i) 1 s (ii) 0.1 s (iii) 0.01 s (iv) 0.001 s
f) One degree on Celsius
scale is equal to ______ degree on Kelvin scale.
(i) 1 (ii) 1.8 (iii) 0 (iv)
100
g)One degree on Celsius scale is equal to ______ degree on Fahrenheit
scale
(i) 5/9 or
0.55 (ii)
9/5 or 1.8 (iii) 5.9 (iv) 9.5
h) A laboratory
thermometer has marking from
(i) 00 C
to 1000 C (ii) 350 C to 420
C
(iii)- 100 C to 1100 C (iv) -100
C to 1000 C
i) A clinical thermometer has marking from
(i) 00 C to 1000 C
(ii) 350 C to 420 C
(iii) - 100 C to 1100 C (iv) -100 C to 1000 C
k) A clinical thermometer marked in 0F has
markings from
(i) 00 F to 1000 F (ii) 950 F to 1100 F
(iii) - 100 F to 1100 F (iv) 980 F to 1100
F
l) If the temperature of a
patient’s body is above ______, it is said to be
suffering from
fever.
(i) 370 C (ii) 350 C
(iii) 380 C (iv)37.50 C
3. Answer in one word
a) According to Kelvin scale the ice point is – 273 K
b) According to Kelvin scale the steam point is – 373 K
c) According to Celsius scale the ice point is – 00 C
d) According to Celsius scale the steam point is – 1000 C
e) According to Fahrenheit scale the ice point is – 320 F
f) According to Fahrenheit scale the steam point is – 2120 F
g) The outer tube of the thermometer is called – Capillary tube.
h) It converts the load in to electrical signal – load cell.
i) The electronic part
which processes the electrical signal and display
the mass – The signal conditioner.
j) The load bearing part that transfers the load of the
object to the load
cell – The structure.
k) The pendulum completes one to and fro oscillation in – 2 s.
m) Device which is used for measuring the timing of athletic
activities
is – Electronic stop watch.
n) Number of divisions
between the ice point and steam point in the
Celsius scale is – 100.
o) Number of divisions between the ice point and steam point
in the
Kelvin scale is – 100.
p) Number of divisions
between the ice point and steam point in the
Fahrenheit scale is – 180.
q) The long part of the capillary is called – Stem
r) This prevents the mercury from falling back
all by itself – Constriction.
4. Convert the following quantities as
indicated.
a) 10 quintal = ________
metric ton.
b) 1 cm = _________ metre. c)
1 mm = ________ metre.
d) 1 yard = ________ ft. e)
1 decimetre = ________ meter.
f) 1 decametre = ________ metre. g) 1 hectometre = _________ metre
h) 1 gram = _________ kg. i) 1 mg = _______ kg.
j) 1 lb = _______ g. k) 1 h = ________ s
l) 1 year = ________
s. m) 1 day = ________ s.
n) 1 decametre2
= ________ m2. o)
1 hectare = _________ m2
p) 1 km2 =
_________ m2. q) 1 dm2 = ________ cm2
r) 1 cm2 =
_________ m2 s) 1 mm2 = ________ m2
t) 1 square yard =
________ m2 u)
1 square ft = ________ m2
v) 1 acre = _________
m2
Ans. a) 1, b) 0.01, c) 10-3, d) 3,
e) 0.1, f) 10, g) 100, h) 10-3, i) 10-6,
j) 453.59, k) 3600, l) 3.15 x 107, m) 86400,
n) 100, o) 104, p) 106,
q) 100, r) 10-4, s) 10-6, t) 0.836, u) 0.09290, v) 4046.856
5. Match the following columns.
Column A Column
B
i) Unit of length in C.G.S a) up to 0.01 mm
ii) Unit of mass in F.P.S b)
Electronic stop watch
iii) Metre ruler can measure c)
are
iv) Screw gauge can measure d)
centimetre
v) Mass of 1 litre water at 40 C e) degree
vi) It converts load in to f)
measures accurately up to
electrical signal 0.01 s
vii) Measures the time of athletic g) pound
activities
viii) each division in thermometer h) 1 kilogram
ix) Decametre square is also called i) the load cell
x) Electronic stop watch j)
up to 1 mm
Ans. i-d, ii-g,
iii-j, iv-a, v-h, vi-i, vii-b, viii-e, ix-c, x-f
B. Short Questions and Answers
1. Why do we use the multiples and submultiples
of a unit?
Sometimes the size of a unit to express a physical quantity
may not be
convenient. It may be either too small or too big. So we use
the multiples
and submultiples of a unit.
2. What are the multiple and submultiple unit
of mass?
The multiple units of mass are quintal, metric tonne and
submultiple
of mass are gram, milligram.
3. What is a mean solar day?
The mean of 365 solar days in a year is called the mean solar
day. We
measure time in terms of the mean solar day.
4. Name the scientists after whom degree
celsius and degree Fahrenheit
is named.
The degree celsius is named after the scientist Andrews
Celsius and
degree Fahrenheit is named after scientist Gabriel Daniel
Fahrenheit.
5. Why the Celsius scale is also called
centigrade scale?
There are 100 divisions between the ice point and the steam
point in
the Celsius scale. So it is also called as centigrade scale.
6. Show the ice point, steam point and the
number of degrees in between
the ice point and steam point in all the three
scales to measure
temperature.
Scale of Temperature
|
Ice point
|
Steam point
|
Number of degrees between ice point
and steam point
|
Kelvin
|
273 K
|
373 K
|
100
|
Celsius
|
00 C
|
1000 C
|
100
|
Fahrenheit
|
320 F
|
2120 F
|
180
|
7. What is the area of a circular lamina of
radius r?
Area of a circular lamina = ℼ x (radius)2 = ℼr2
Where ℼ = 22/7
or 3.14
8. What are the submultiple and multiple units
of area?
The submultiple unit of area are square decimetre, square
centimetre,
square millimetre and the multiple units of area are
decametre square,
hectare, square kilometre.
9. Describe one hectare.
One hectare is the area of a square of each side 100 metre.
1 hectare = 100 metre x 100 metre
= 10000 metre2 or 104 m2
10. Describe one are (Decametre square)
One square decametre (are) is the area of a square of each
side 1
decametre or 10 metre
So 1 decametre2 = 10 metre x 10 metre
= 100 meter2
11. Define a square metre.
A square metre is the area of a square of each side of 1
metre.
12. What the red arrow in a thermometer
indicates?
The body temperature of a healthy person is 370 C
or 98.60 F. This
temperature is marked by a red arrow in a clinical
thermometer.
C. Long Questions and Answers
1. Define the following.
(a) Metre ruler (b) Measuring tape (c) Parallax error
a) Metre ruler:
A metre ruler is used to measure length. It is one metre long
and is
divided in to 100 equal parts. Each part is a centimetre.
Each
centimetre us further divided in to 10 equal parts. Each
small part is a
millimetre. It can measure a length correct up to 1 mm. These
are also
available in the length of 15 cm, 30 cm and 50 cm.
b) Measuring tape:
A measuring tape is a flexible ruler. It consists of a ribbon
of cloth,
plastic, fibre glass or metal strip. It has lines as markings
in cm and mm.
It can be easily carried in pocket. It is available in
various lengths
such as, 1 m, 5 m, 10 m, 50 m and 100 m.
c) Parallax error:
A ruler has some thickness. While looking at the readings on
the scale,
we get different readings, when the eye kept at different
positions.
This is called error of parallax. To avoid it the eye should
be kept in
front of and in line with the reading to be taken.
2. Describe an electronic balance.
Electronic balance is used for precise and accurate
measurement of
mass of an object. An electronic balance has three parts.
·
The
structure: It is the load bearing part which transfers the load of
the object to the load cell.
·
The
load cell: It converts the load in to electrical signal.
·
The
signal conditioner: It is the electronic part which process the
Electrical signal and display the
mass.
Electronic balance measures the mass automatically. It
directly
measures the mass of the object and display it in the digital
form on
the screen.
3. How a patient’s body temperature is measured
with a clinical
Thermometer?
Before using the thermometer the bulb of thermometer is
washed in
cold water. Then it is slightly jerked to bring the mercury
level in its
capillary tube below the mark 370 C. To measure
the temperature of
patient’s body its bulb is kept either below the tongue or
under the
arm’s pit of the patient for about a minute. After one minute
the
thermometer is taken out and the reading is noted. If the
reading is
above 370 C the patient is said to have fever.
4. What are fundamental quantities and derived
quantities of
measurement? Show the relation
between them with examples.
The physical quantities like length, mass time and temperature
are
called the fundamental quantities. On the other hand area,
volume,
speed etc. are the quantities which are expressed in terms of
the
measurable fundamental quantities like length, mass and time
etc.
these are called derived quantities. For example:
Area = Length x breadth
Volume = Length x breadth x height
Speed = Distance /
Time
5. Define the formula for area of a square, rectangle, triangle
and circle.
Area
of a square of side l
=
side x side = l x l = l 2
Area
of a rectangle of length l and breadth b
=
length x breadth = l x b = l b
Area
of a triangle of length of base l and height h
=
1/2 length of base x height = 1/2
l h
Area
of a circle of radius r
=
π(radius)2 = πr2 ( Where π = 22/7 )
6. A lawn is in the shape of a square. Find the area covered by
the lawn if
one
of its side is 40 m.
Area
of the lawn = side x side
=
40 m x 40 m
=
1600 m2
Therefore the area covered
by the lawn is 1600 m2.
7. Find the area of a circle whose radius is 7
m.
Area of the circle = π(radius)2
= (22/7 x 7 m x 7 m)
= (22 x 7 x 7) m2
= 1078 m2.
8. Find the area of a rectangular field whose
length is 40 metre and
breadth is 25 metre.
Area of the rectangular field = Length x breadth
= 40 m x 25 m = (40 x 25) m2
= 1000 m2.
9. The length of the base of a triangle is 12
metre and its height is
4 metre. What is the area of the triangle?
Area of the triangle = 1/2
length of base x height
= 1/2
x 12 m x 4 m = (6 x 4) m2
=
24 m2
10. Convert 1 km2 in to m2.
1 km2 = 1 km x 1 km
= 1000 m x 1000 m
= 1000000 m2
= 106 m2
11. Convert 1 cm2 and 1 mm2 in to m2.
1 cm2 = 1 cm x 1 cm
= (1/100m) x
(1/100m)
=
1/10000 m2 = 10-4 m2
1
mm2 = 1 mm x 1 mm
=
(1/1000m) x (1/1000m)
=
1/1000000 m2 = 10-6 m2
12. Solve the given numerical.
a) Convert (i) 00 C in kelvin scale (ii) 238.16 K in Celsius scale
b) Convert (i) 12:30 a.m. in to 24-hr time (ii) 19:25 in to 12-hr time
c) Express (i) 2.25 m in cm (ii)
8000g in kg
a)
(i) Kelvin = Celsius + 273
00
C = 0 + 273 = 273 K
(ii)
Celsius = Kelvin -273
238.16
K = 238.16 – 273 = -34.860 C
b)
(i) 12:30 a.m in 24-hr clock is 12:30
(ii)
19:25 in 12-hr time is 7:25 p.m
c)
(i) 2.25 m = 2.25 x 100 = 225 cm
(ii)
8000g = 8000 ÷ 1000 = 8 kg
13. A piece of wire is wound around a pencil 40 times. If the
width of all
the turns is 2 cm find the diameter of the wire.
Length
of 40 turns is 2 cm
So
diameter of the wire = length of total turns ÷ 40
=
2 cm ÷ 40 = 200 mm ÷ 40
=
5 mm
Thank You !. For These Questions
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