CBSE Class 6 Science Chapter 5: Measurement of Length and Motion — Assertion & Reason
CBSE Class 6 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions are based on Chapter 5: Measurement of Length and Motion from the NCERT Class 6 Science textbook Curiosity. Each question has four options — read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): Standard units of measurement are necessary for uniform measurements.
Reason (R): Measurements using body parts like handspans vary from person to person.
Reason (R): Measurements using body parts like handspans vary from person to person.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because body parts differ in size, standard units like the metre are required to ensure measurements are consistent globally.
2
Assertion (A): The SI unit of length is the kilometre.
Reason (R): The International System of Units (SI units) is adopted globally to avoid confusion in measurements.
Reason (R): The International System of Units (SI units) is adopted globally to avoid confusion in measurements.
Answer: (d)
A is false, but R is true. The SI unit of length is the metre (m), not the kilometre. The International System of Units ensures consistency worldwide.
3
Assertion (A): It is convenient to measure the distance between two cities in millimetres.
Reason (R): For measuring large distances, we use a larger unit called a kilometre.
Reason (R): For measuring large distances, we use a larger unit called a kilometre.
Answer: (d)
A is false, but R is true. It is highly inconvenient to measure city-to-city distances in millimetres; kilometres are used for such large measurements.
4
Assertion (A): While measuring length, the eye must be exactly in front of and directly above the point of measurement.
Reason (R): Looking from an angle leads to incorrect readings on the scale.
Reason (R): Looking from an angle leads to incorrect readings on the scale.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Proper eye positioning prevents parallax errors, ensuring the measurement is read accurately.
5
Assertion (A): A scale with a broken zero mark cannot be used to measure length.
Reason (R): If the zero mark is broken, you can place the object at any other full mark and subtract it from the final reading.
Reason (R): If the zero mark is broken, you can place the object at any other full mark and subtract it from the final reading.
Answer: (d)
A is false, but R is true. A broken scale can still be used. You simply align the object with another clear mark (e.g., 1.0 cm) and subtract that initial value from the final reading.
6
Assertion (A): A rigid metre scale is best suited to measure the girth of a tree or a curved line.
Reason (R): Curved lines can be accurately measured using a flexible measuring tape or a thread.
Reason (R): Curved lines can be accurately measured using a flexible measuring tape or a thread.
Answer: (d)
A is false, but R is true. A rigid scale cannot bend around a tree trunk. Flexible measuring tapes or threads are required for curved or circular surfaces.
7
Assertion (A): To state whether an object is at rest or in motion, a reference point is required.
Reason (R): Motion is defined as a change in position with respect to a fixed reference point over time.
Reason (R): Motion is defined as a change in position with respect to a fixed reference point over time.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. You cannot determine if an object has moved unless you compare its position to a fixed stationary point.
8
Assertion (A): Passengers sitting in a moving bus are at rest with respect to each other.
Reason (R): The position of the passengers is not changing with time with respect to the bus.
Reason (R): The position of the passengers is not changing with time with respect to the bus.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Since the distance between the passengers and the bus itself remains constant, they are relatively at rest inside the vehicle.
9
Assertion (A): The march-past of soldiers in a parade is an example of circular motion.
Reason (R): When an object moves along a straight line, its motion is called linear motion.
Reason (R): When an object moves along a straight line, its motion is called linear motion.
Answer: (d)
A is false, but R is true. A march-past is an example of linear motion because the soldiers march forward in a straight line, not in a circle.
10
Assertion (A): An eraser tied to a thread and whirled by hand exhibits circular motion.
Reason (R): The eraser moves continuously along a circular path.
Reason (R): The eraser moves continuously along a circular path.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Any object moving along a circular path is undergoing circular motion.
11
Assertion (A): A child playing on a swing undergoes oscillatory motion.
Reason (R): Oscillatory motion occurs when an object moves to and fro about a fixed position.
Reason (R): Oscillatory motion occurs when an object moves to and fro about a fixed position.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. A swing constantly moves back and forth from its resting central position, which is the definition of oscillatory motion.
12
Assertion (A): Both circular and oscillatory motions are periodic in nature.
Reason (R): In both these motions, the object repeats its path after a fixed interval of time.
Reason (R): In both these motions, the object repeats its path after a fixed interval of time.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Periodic motion is any motion that repeats at regular intervals, which applies to both circular orbits and back-and-forth oscillations.
13
Assertion (A): The symbol for five centimetres should be written as '5 cms'.
Reason (R): Symbols for units are never followed by 's' for the plural.
Reason (R): Symbols for units are never followed by 's' for the plural.
Answer: (d)
A is false, but R is true. By scientific convention, unit symbols are never pluralised. It should be written simply as '5 cm'.
14
Assertion (A): The length of a curved line can be measured by tracing it with a thread.
Reason (R): The thread can be straightened and its length measured on a standard metre scale.
Reason (R): The thread can be straightened and its length measured on a standard metre scale.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. A thread conforms to the curve, and once straightened, it accurately transfers that length to a straight scale.
15
Assertion (A): Units like angula (finger width) and foot are still used by some traditional craftspeople.
Reason (R): These units provide exactly the same measurement for every person.
Reason (R): These units provide exactly the same measurement for every person.
Answer: (c)
A is true, but R is false. While traditional units are still used by some craftspeople like tailors, they do NOT provide exactly the same measurement for everyone because body sizes vary.
16
Assertion (A): A metal strip pressed at one end and released at the other undergoes linear motion.
Reason (R): The free end of the strip moves up and down repeatedly about a fixed position.
Reason (R): The free end of the strip moves up and down repeatedly about a fixed position.
Answer: (d)
A is false, but R is true. Because the strip moves up and down about a fixed position, its motion is oscillatory, not linear.
17
Assertion (A): Kilometre stones on a highway indicate the distance with respect to a specific destination.
Reason (R): The destination city acts as a reference point for measuring the distance.
Reason (R): The destination city acts as a reference point for measuring the distance.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Kilometre stones use the destination city as the fixed reference point to tell travellers how far they are from it.
18
Assertion (A): 1 metre is equal to 1000 millimetres.
Reason (R): 1 metre equals 100 centimetres, and 1 centimetre equals 10 millimetres.
Reason (R): 1 metre equals 100 centimetres, and 1 centimetre equals 10 millimetres.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because each of the 100 centimetres contains 10 millimetres, the total is 100 x 10 = 1000 millimetres in a metre.
19
Assertion (A): An object can be considered to be at rest and in motion at the same time.
Reason (R): Motion is relative and depends entirely on the chosen reference point.
Reason (R): Motion is relative and depends entirely on the chosen reference point.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. A passenger is at rest relative to the bus but in motion relative to the trees outside. Motion is entirely dependent on the observer's reference point.
20
Assertion (A): An orange falling from a tree to the ground is an example of linear motion.
Reason (R): The orange moves along a straight line towards the ground.
Reason (R): The orange moves along a straight line towards the ground.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Objects dropping straight down under gravity follow a straight-line path, making it linear motion.
❓ Frequently Asked Questions
What is covered in CBSE Class 6 Science Chapter 5 Measurement of Length and Motion?
This chapter covers all key topics from Measurement of Length and Motion as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 6 board exam preparation covering the complete syllabus.
Are these CBSE Class 6 Science Assertion & Reason updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 6 Science?
All chapters of CBSE Class 6 Science are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study Measurement of Length and Motion online for free?
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