Chapter 1: Measurement in Science and Technology

Chapter 1: Measurement in Science and Technology Class 10 Science and Technology (NIOS Textbook Solutions)

Chapter 1. MEASUREMENT IN SCIENCE AND TECHNOLOGY   

INTEXT QUESTIONS 1.1

1. Define the term measurement by giving two examples.

Answer:  Measurement is the process of comparing an unknown physical quantity with a fixed standard unit to determine its value.

Examples: (a) Measuring the length of a table in metres (m).

(b) Measuring the mass of a bag in kilograms (kg).

2. What is a unit?

Answer: A unit is a measure, device or a scale in terms of which we make physical measurement.

3. List the essential characteristics of a unit.

Answer: The essential Characteristics of a unit:

(i) Relevant: The unit should be suitable and appropriate for measuring the given physical quantity.

(ii) Convenient : The unit should be easy to use, practical, and accepted universally.

(iii) Well Defined : The unit should have a clear and fixed meaning so that measurements remain accurate and consistent everywhere.

INTEXT QUESTIONS 1.2

1. Name the smallest unit of length during the Chandragupta Maurya period.

Answer: The smallest unit of length during the Chandragupta Maurya period is Paramanu.

2. List the parts of human body which can be used for measurements.

Answer: The parts of the human body which can be used for measurements are arm, angul (finger width), cubit, hand span and foot.

3. Why cannot the parts of human body be used for accurate measurement?

Answer: The parts of the human body cannot be used for accurate measurement because they vary from person to person, and we cannot trust our senses to measure exactly and accurately.

4. In which period was ‘gaz’ introduced as a unit to measure length?

Answer: The unit ‘gaz’ was introduced as a unit to measure length during the Mughal period in India.

INTEXT QUESTIONS 1.3

1. Differentiate between base units and derived units.

Answer: The difference between base units and derived units are :

Base (Fundamental) Units	derived units
(i) Fundamental units are only seven in number whereas derived units are very large in number.	(i) Derived units are formed in large numbers from base units.
(ii) (b) Fundamental units are independent of each other.	(ii) Derived units are obtained from fundamental units.

2. What is the difference between mass and amount of a substance?

Answer:  Mass and amount of substance are different physical quantities are:

Mass	Amount of Substance
(i) Mass is the quantity of matter present in a substance.	(i) Amount of substance tells how many particles (atoms, molecules, ions… etc.) are present.
(ii) Measured using a balance.	(ii) Calculated using number of particles or molar mass.
(iii) Depends on the total matter present.	(iii) Depends on the number of entities present.
SI unit: kilogram (kg)	SI unit: mole (mol)

3. Derive the unit of Pressure. (Pressure = Force/Area)

Answer:  We have,  

 

 

So, the SI unit of pressure is  .

4. Which term of measurement is commonly used by the announcer of your favourite radio programme?

Answer:  The announcer of my favourite radio programme commonly uses frequency as the term of measurement. It is measured in hertz (Hz).

5. Observe a bulb/tube light at your home for the unit measurement written on it. From Table 1.3 find out the physical quantity it measure?

Answer:  The physical quantity measured is Power.
SI unit of Power = Watt (W).

Example: A 9 W LED bulb means the bulb uses 9 watts of power.

6. Veena, Mohindar and Alam went to market. Veena brought milk with a litre measure, Mohindar brought ribbon by a measuring mark on the table and Alam brought vegetables using stones. Which of them did not use the appropriate measurement while purchasing goods? Explain while given the names of right measurement.

Answer: Mohindar and Alam did not use appropriate measurements. Mohindar should buy ribbon using a metre scale to measure length. Alam should buy vegetables using kilogram (kg) to measure mass. Veena used the correct unit for milk (litre).

INTEXT QUESTIONS 1.4

Rewrite the following measurements of length using suitable SI prefixes.

(i) effective radius of a proton ;  m __________

(ii) radius of human red blood cell ;  ________

(iii) radius of our galaxy ;  __________________

You must follow the following rules while using SI prefixes.

Answer: (i) Effective radius of a proton ;(femtometre)

[  ]

(ii) Radius of human red blood cell ;   (micrometre)  

      [ ]

(iii) Radius of our galaxy ;  (exametre)

[  ]

TERMINAL EXERCISE

1. Which of the following is not an SI unit?

A. Metre     B. Pound       C. Kilogram    D. second

Answer:  B. Pound

[ Pound is not an SI unit. It is a unit of mass mainly used in some countries, while kilogram is the SI unit of mass.]

2. If the mass of a solution in 10 μg it is the same as

A.    B.       C.       D.   

Answer:  A.      

[ We have,   ]

3. Indicate whether the following statements are True or False. Write T for true and F for false

(i) SI units are arbitrary   (ii)     (iii)   (iv) SI unit for pressure is Pascal

Answer: (i) True

[ SI units are internationally accepted standard units.]

(ii) False

[ We have, ]

(iii) False

[ We have,  ]

(iv) True

[ The SI unit of pressure is Pascal (Pa). ]

4. Represent the following measurements by using suitable SI prefixes

(i)         (ii)            (iii)     (iv) 200,000 kg

Answer: (i)  (nanoseconds) 

(ii)   (picometres)

(iii)  (micromoles)

(iv)  (megagrams)

5. Give the SI units used while buying :

A. Silk ribbon           B. Milk             C. Potatoes

Answer:  A. Silk ribbon → metre (m) (used for measuring length)
B. Milk → litre (L) (commonly used unit of volume)
C. Potatoes → kilogram (kg) (used for measuring mass)

6. Give the common unit to measure our body temperature and write its SI unit

Answer: The common unit used to measure our body temperature is degree Celsius (°C). The SI unit of temperature is kelvin (K).

7. What are the advantages of SI units ?

Answer:  The advantages of SI units are :

(i) Internationally accepted: SI units are used all over the world, making communication easier.

(ii) Uniform system: It provides one standard system of measurement for everyone.

(iii) Easy conversion: Conversion between units is simple because it is based on powers of 10.

(iv) Well-defined units: SI units are clearly defined and accurate.

(v) Convenient for scientific work:  They help in calculations and comparison of measurements.

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