# solutions for chapter measurement

Exercise

**A.Fill in the blanks**

- One kilometre equals ………………….. Centimetres.
- A year has ……… days.
- The interval between two events is called ……..
- The distance between any two cities is measures in …………………….
- The unit of mass is …………………………………….
- ………………….are used to measure time .
- All measuring ……………… have standard marking for accurate measurement.

Ans :

- 100000 centimetres
- 365 days
- Time
- Km
- Kilogram
- Watches
- Device

**Write ‘T’ For true and ‘F’ for False**.

- To prepare clothes a tailor should take measurement of Clothes .
- Mana and Pathi units are used in our Villages.
- Weight of Small quantites are measured by physical balance.
- Mass of body varies from place to place .
- Newton is called as derived unit
- One gram is equal to one hundred milligrams.
- The standard unit of time is hour.

Ans:

- True
- True
- True
- False
- True
- False
- False

**Answer the following questions.**

- What is Measurement? Write the importance of Measurement?

Ans:

Measurement is the comparison between known and unknown quantities.

Importance of measurement:

- Helps to find actual size.
- Main basis for buying and selling.
- Vital role in purchase and sale .
- Helps in daily life activities etc.

- What do you understand by physical quantities?

The quantities which can be measured are called physical quantities.

mass,length,temperature ,time are the physical quantities.

- Write the SI units of mass,length and time.

Ans:-

SI units of:

Mass = Kilogram (kg)

Length =meter (m)

Time = second (s)

- Define :

i.MKS

ii.CGS

iii. FPS

- SI system

Ans :

i.

MKS is the modern system in which length is measured in Meter,Mass is measured in kilogram and Time is measured in seconds.

- CGS

CGS is the French system of units.In this system of units length is measured in centimeter,mass is measured in gram and time is measured in seconds.

iii.

FPS

FPS is the british system of units in which length is measured foot ,mass is measured pound and time is measured in seconds.

iv.

SI system

This is Extended form of the MKS system.It is the short form of System of international units.

- Write the two demits of traditional measurement?

Ans :-

The two demerits of traditional measurement are :

- Not accepted all over the world.
- Can not give accurate measure.

- Why standard unit of measurement is necessary?

Ans :- standard unit of measurement is necessary because it brings uniformity all over the world.

- Why can’t hand span be used as standard unit of length measurement?

Ans :Hand span is different in different people therefore it does not brings uniformity .that is why we can not use hand span as standard unitof measurement.

- Can we use an elastic measuring tape for accurate measurement of distances?mention some of the difficulties you might face in using such measuring tape.

Ans :

Elastic measuring tape is strechable and therefore can not be used as accurate measuring device.

Difficulties to be faced during measurement:

- Wrong marking
- Placing ruler in exact place
- Eye on the top of the point.

- How would you weigh an object using a beam balance?

Ans :- beam balance is used to weigh mass of object by comparing with known body.there are two pans and we put unknown object in one and on other on known object.

- What precaution should be taken while measuring length?

Ans:-

Following are the precaution to be taken while measurig length :-

- Choosing the right measuring tape.
- Placing the ruler in exact place.
- Fixing eye on the top of the point.

- How many quintals are there in one ton?

Ans:-

we know, 1 ton = 1000 kilogram

1 quintal = 100 kilogram

So ,there are 10 quintal in one ton.

- Express 4.20 m length in millimeter unit.

Ans :-

We know, 1 m = 100 cm

1 cm = 10 mm

So , 4.20 m = 4.20 *100*10

= 4200 mm

- How many seconds are there in 6.5 minutes?

Ans :-

We know, 1 mimute = 60 sec

So, 6.5 minutes = 6.5 * 60 sec

= 3900 sec

- A scale has 10 divisions between two consecutive centimeter marking .what is the minimum distance that can be measured using this scale ?

Ans :-

Since the scale has 10 division between two consecutive centimeter marking ,the minimum distance to be measured is 1 mm.

- While measuring the length of wooden box ,the reading of the scale at one end is 4.8 cm and at the other end it is 48.2 cm. what is the length of the box?

Ans :-

One end = 4.8 cm

Another end = 48.2 cm

Length of the box = another end –one end

=48.2-4.8

= 43.4 cm

- Convert the following:

- 700 meters into kilometers

Ans :- we know ,

1000 meters = 1 km

1 m = 1/1000 km

700 m = 1/1000* 700

= 0.7 km

- 5620 grams into kilograms

Ans :- we know.

1 kg = 1000 gms

So, 5620 grams = 5620/1000 kgs

= 5.62 kg

- 120 seconds into minutes.

Ans :- we know,

60 seconds = 1 min

So, 120 seconds = 120/60 = 2 minutes.

- 5 kg into grams

Ans :- we know 1 kg = 1000 grams

So, 8.5 kg = 8.5*1000 = 8500 grams

- 7 days into seconds.

Ans :- we know,

1 day = 24 hours

1 hours = 60 minutes

1 min = 60 seconds

Now, 7 days = 7 *24*60*60

= 604800 seconds.

- 55 seconds into minutes.

Ans:-

We know,

1 min= 60 seconds

Now, 55 seconds = 55 / 60 seconds

- 7 hours into seconds.

Ans :- we know,

1hour = 60 min

1 min = 60 sec

Now, 7 hours = 7*60*60.

=25200 seconds

- 20 cm into meters

Ans :-

We know,

1 m = 100 cm

So,

20 cm = 20/100 m

= 0.2 m

- 7 km into centimeters

Ans :- we know ,

1 km = 1000 m

1m = 100 cm

So , 3.7 km = 3.7*1000*100

= 370000 cm

Thanks for your time ,

Best of luck.