Chapter 1 Measurement in Science and Technology

NIOS Class 10 Science Chapter 1 Question Answers

INTEXT QUESTIONS 1.1

1. Define the term measurement by giving two examples.

Ans: Measurement may be defined as a kind of counting. It refers to the counting of the number of times a chosen scale is used to make the measurement. For example: An inch tape to measure length, or a graded cylinder to measure volume.

2. What is a unit?

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

3. List the essential characteristics of a unit.

Ans: A standard unit must have the following characteristics to be useful

relevant
convenient
well defined.

INTEXT QUESTIONS 1.2

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

Ans: Parmanu

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

Ans: Arm, Angul, Cubit, etc.

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

Ans: Because the parts of the human body may 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?

Ans: During the period of the Mughal emperor Akbar.

INTEXT QUESTIONS 1.3

1. Differentiate between base units and derived units.

Ans:

(a) Fundamental units are only seven in number, whereas derived units are very large in number.
(b) Fundamental units are independent of each other, but derived units are obtained from fundamental units.

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

Ans: Mass of a body is the amount of matter contained in a body, while the amount of the substance is equal to its molecular mass.

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

Ans: Unit of pressure = Unit of force/Unit of area = kg ms^-2 / m² = kg m^-1s^-2

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

Ans: 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 measures.

Ans: Watt

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.

Ans: Mohindar and Alam, meter scale, kilogram

INTEXT QUESTIONS 1.4

Rewrite the following measurements of length using suitable SI prefixes.

(i) effective radius of a proton; 1.2 × 10^–15m __________

(ii) radius of human red blood cell; 3.7 × 10^–6m ________

(iii) radius of our galaxy; 6 × 10¹⁹m __________________

You must follow the following rules while using SI prefixes.

Ans:

(i) 1.2 fm
(ii) 3.7 mm
(iii) 60 E m

TERMINAL EXERCISE

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

A. Metre

B. Pound

C. Kilogram

D. second

Ans: B. Pound

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

A. 10^–6 g

B. 10^–12 g

C. 10^–9 g

D. 10^–3 g

Ans: A. 10^–6 g

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

(i) SI units are arbitrary

(ii) 1 mm² = 10^–3 m²

(iii) 10^–15 g = 1 mpg

(iv) SI unit for pressure is Pascal

Ans:

(i) False (F)

(ii) False (F)

(iii) False (F)

(iv) True (T)

4. Represent the following measurements by using suitable SI prefixes

(i) 2 × 10^–8 s

(ii) 1.54 × 10^–10 m

(iii) 1.98 × 10^–6 mol

(iv) 200 000 kg

Ans:

(i) 2 × 10^–8 s – nano

(ii) 1.54 × 10^–10 m – nano

(iii) 1.98 × 10^–6 mol – micro

(iv) 200 000 kg- mega

5. Give the SI units used while buying :.

A. Silk ribbon

B. Milk

C. Potatoes

Ans:

A. Silk ribbon – Meter

B. Milk – Litre

C. Potatoes – Kilogram

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

Ans: °C (degree Celsius). Its SI unit is Kelvin (K).

7. What are the advantages of SI units?

Ans: Advantages of SI Units:

SI units are used all over the world, which makes scientific communication clear and uniform.
All SI units are based on the decimal (powers of 10) system, so converting from one unit to another is simple.
Derived units are formed without introducing extra numerical factors, making calculations easier and more consistent.
SI units are defined using precise scientific standards, ensuring accuracy and reproducibility in measurements.
The system covers all types of measurements—length, mass, time, temperature, electric current, etc., using a small set of basic units.
Using SI units avoids confusion caused by multiple unit systems and ensures uniformity in science, technology, trade, and industry.