The comprehensive approach in SCERT Class 8 Basic Science Textbook Solutions Chapter 1 Measurement and Units Important Questions ensure conceptual clarity.
Measurement and Units Extra Questions and Answers Class 8 Basic Science Chapter 1 Kerala Syllabus
Measurement and Units Class 8 Important Questions
Question 1.
Find out the odd one from following units and write it down.
a) m
b) g
c) kg
d) mg
Answer:
a) m
All others are the units of mass.
Question 2.
How much time does light take to travel 3 lakh kilometre in vacuum?
(1s, 1/2s, 2s, 3s)
Answer:
1s
Question 3.
Find out the correctly written unit from those given below.
(Volt, pascal, Kelvin, Ampere)
Answer:
pascal
Question 4.
SI unit of force is ………………………
Answer:
newton (N)
Question 5.
Imagine that the distance from school to your friend’s house is 2250 m. State this in kilometres.
Answer:
2250 m = 2250/1000 km = 2.250 km
Question 6.
Find the odd one.
cm3 kg/m3; mm, m3
Answer:
mm, All others are derived units.
Question 7.
Choose the derived unit from the following.
(m, kg, N, s)
Answer:
N
Question 8.
Select the odd one. State reason.
(m2, m3, m, kg/m3)
Answer:
m. m is a fundamental unit. Others are derived units.
Question 9.
Identify the relation in first word-pair and complete the second one.
Volume : m3
Density : ………………………
Answer:
kg/m3
Question 10.
Write the appropriate unit for expressing the distance between planets in the solar system.
a) m
b) nm
c) AU
d) km
Answer:
c) AU
Question 11.
Pick out the correct representation of units from the following data.
a) 37.65 m
b) 37 m 65 cm
c) 10 Pa
d) 20 Kg
Answer:
Correct representations are a) 37.65 m and c) 10 Pa
Question 12.
Which of the following does not belong to the group?
(km, kg, mm, cm)
Answer:
kg, others are units of length.
Question 13.
A child measures the total thickness of the papers of his science diary having 200 sheets and finds it to be 2 cm. Find the thickness of one of these papers in SI unit.
Answer:
Thickness of one paper = Height of the pile of papers /No. of papers.
Thickness of one paper = 2 cm/200 = 1/100 cm = 0.01 cm
Thickness of paper in SI unit = 0.01 cm/100 = 0.0001 m
Question 14.
Write down the following units in descending order of their values.
a) 2 cm, 2 m, 2 km, 2 mm
b) 5 g, 5 mg, 5 quintal, 5 kg
Answer:
a) 2 km > 2 m > 2 cm > 2 mm
b) 5 quintal > 5 kg > 5 g > 5 mg
Question 15.
Write down the following units in the ascending order of their values.
a) mm, nm, cm, μm
b) 1 m, 1 cm, 1 km, 1 mm
Answer:
a) nm < μm < mm < cm
b) 1 mm < 1 cm < 1 m < 1 km
Question 16.
Complete the table.
Quantity – SI Units
Length – ………………….
Time – ………………….
Area – ………………….
Density – ………………….
Answer:
Length – metre (m)
Time – second (s)
Area – square metre (m2)
Density – kilogram per cubic metre (kg/m2)
Question 17.
Complete the table.
| Unit | Symbol |
| Newton | (a) ………………….. |
| Kelvin | (b) …………………… |
| Ampere | (c) …………………… |
| Metre | (d) ………………….. |
| Kilogram | (e) …………………… |
| Second | (f) ……………………. |
Answer:
(a) N
(b) K
(c) A
(d) m
(e) kg
(f) s
Question 18.
Classify the physical quantities given in the box as fundamental quantities and derived quantities.
| Length, density, area, mass |
| Fundamental quantities | Derived quantities |
Answer:
| Fundamental quantities | Derived quantities |
| Length, mass | Density, area |
Question 19.
1 mm is the least count of a metre scale.
a) What do you mean by least count?
b) Arrange the following units in ascending order of their values.
(μm, km, nm, cm) (Annual 2022)
Answer:
a) The smallest value that can be measured using an instrument is called its least count.
b) nm < μm < cm < km
Question 20.
Based on the fundamental physical quantity length, write down the following questions. (Term 1, 2023)
a) In which unit is the thickness of plastic carry bags expressed?
b) How many kilometres make one astronomical unit?
Answer:
a) micrometre
b) 15 crore kilometre (150 million kilometre)
Question 21.
We know about fundamental units and derived units.
a) What is meant by derived units?
b) Based on which fundamental unit is area expressed?
c) Write down the unit of density.
Answer:
a) Derived units are units that can be stated using fundamental units or that depend on fundamental units.
b) Area (m2) is expressed in terms of the fundamental unit length.
c) Density = mass/volume
The unit of density is kg/m3
Question 22.
Convert the following units into SI units without changing their values.
a) 3500 g
b) 2.5 km
c) 2 h
Answer:
a) 3500 g = 3500/1000 kg = 3.5 kg
b) 2.5 km = 2.5 × 1000 m = 2500 m
c) 2 h = 2 × 60 × 60 s = 7200 s.
Question 23.
State whether the following symbol are right or wrong. Correct them if wrong.
a) m/s/s
b) kilogram per cubic metre
c) 100 n
d) 20 kgs
e) 3M
f) 1 kg 500 g
Answer:
a) Wrong, m/s2 is the correct form.
b) Right
c) Wrong. 100 N is the correct form.
d) Wrong. 20 kg is the correct form.
e) Wrong. 3 m is the correct form.
f) Wrong. 1.5 kg or 1500 g is the correct form