Class 6 Science Chapter 5 Extra Questions and Answers – Measurement of Length and Motion
Class 6 Science Chapter 5 Extra Questions and Answers for “Measurement of Length and Motion” (based on NCERT textbook Curiosity ).
EXTRA IMPORTANT QUESTIONS WITH ANSWERS – Chapter 5 – Measurement of Length and Motion
This includes All types of Questions normally asked in school exams, tests, and NCERT exercises.
CLASS 6 SCIENCE – CHAPTER 5
MEASUREMENT OF LENGTH AND MOTIONEXTRA IMPORTANT QUESTIONS WITH ANSWERS
A. VERY SHORT ANSWER QUESTIONS (1 mark each)
1. What is the SI unit of length?
Answer: Metre (m).
2. What is the smallest unit shown on a 15 cm scale?
Answer: 1 millimetre.
3. What do we call a fixed point from which distance is measured?
Answer: Reference point.
4. What type of motion does a swing show?
Answer: Oscillatory motion.
5. What is 1 km equal to in metres?
Answer: 1000 metres.
6. Which measuring tool is used to measure the girth of a tree?
Answer: Flexible measuring tape.
7. What is meant by char angula?
Answer: Four finger-widths.
8. What causes parallax error?
Answer: Wrong position of the eye while reading a scale.
9. What type of motion does an object show when it moves in a straight line?
Answer: Linear motion.
10. Name one non-standard unit of length.
Answer: Handspan.
B. SHORT ANSWER QUESTIONS (2 marks each)
11. Why do measurements using body parts differ from person to person?
Answer: Body parts like handspan, arm length, and foot size vary among individuals. Therefore, measurements taken using these units give different results.
12. Why are standard units necessary?
Answer: To ensure uniformity and accuracy in measurement. Different people should get the same result when measuring the same object.
13. Why is a metre scale not suitable for measuring the girth of a tree?
Answer: A metre scale is rigid and cannot bend around curved surfaces. A flexible tape is needed.
14. How does the position of the eye affect measurement?
Answer: If the eye is not directly above the marking, the reading appears shifted, causing parallax error and incorrect measurement.
15. Why are kilometre stones useful for travellers?
Answer: They show the distance from a reference point (city), helping travellers know how far they are from their destination.
16. What is meant by periodic motion? Give an example.
Answer: Motion that repeats itself after equal intervals of time. Example: Motion of a pendulum.
17. What is the correct way to measure with a broken scale?
Answer: Start from any clear full mark (such as 1 cm), take the final reading, and subtract the starting reading.
C. SHORT ANSWER QUESTIONS (3 marks each)
18. What precautions must be taken while measuring length with a scale?
Answer:
- The scale must be placed exactly along the length of the object.
- The eye should be directly above the reading point.
- Avoid using scales with unclear or broken zero; use another mark and subtract readings.
19. Distinguish between standard and non-standard units.
Answer:
Standard units: Fixed, universally accepted (metre, centimetre).
Non-standard units: Vary from person to person (handspan, arm length, foot).
20. Explain with an example how reference point affects motion.
Answer: A passenger inside a moving bus appears at rest to another passenger (reference point = bus). But the same passenger appears moving when viewed from outside objects like trees (reference point = roadside).
21. Why do we use different units such as mm, cm and m?
Answer:
mm for very small objects (coin thickness),
cm for medium objects (pencil, mobile),
m for large distances (room length, playground).
22. Compare linear, circular and oscillatory motion.
Answer:
Linear: Straight-line path.
Circular: Moves along a circle.
Oscillatory: Moves to and fro about a fixed point.
D. LONG ANSWER QUESTIONS (4 marks each)
23. Explain the correct method of measuring the length of a curved line.
Answer:
- Take a thread and place it exactly along the curved line.
- Mark the starting and end points on the thread.
- Straighten the thread.
- Measure its length with a scale.
This gives the length of the curved line accurately.
24. Describe the different types of motion with examples.
- Linear motion – Moving in a straight line. Example: Car moving on a straight road.
- Circular motion – Moving in a circular path. Example: Hands of a clock.
- Oscillatory motion – To and fro movement. Example: Swing or pendulum.
- Periodic motion – Repeats at equal intervals. Example: Earth revolving around Sun.
25. Why do children get different measurements of the same table using handspan but get similar results using a metre scale?
Answer:
Handspans differ in size for each child, resulting in different measurements.
A metre scale has a fixed, standard size, so measurements become uniform and same for everyone.
E. HOTS (Higher Order Thinking Skills) QUESTIONS
26. A boy measures his book’s length starting from 2 cm on a scale instead of 0 cm and reads 15 cm. What is the actual length?
Answer:
Actual length = 15 – 2 = 13 cm.
27. Why does a passenger in a bus feel at rest even when the bus is moving?
Answer:
Because the passenger’s position does not change relative to the bus. The bus is the reference point.
28. Can an object be at rest and in motion at the same time? Explain.
Answer:
Yes. A person sitting in a moving bus is at rest relative to the bus, but in motion relative to objects outside.
29. A pendulum swings 30 times in 1 minute. What type of motion is this?
Answer:
Oscillatory motion (periodic motion).
30. Why is stretchable rubber unsuitable for making a metre scale?
Answer:
Because it stretches, changing length each time, giving incorrect measurements.
F. APPLICATION-BASED QUESTIONS
31. Your friend reads a 12 cm line as 13 cm. What could be the mistake?
Answer:
The eye was not placed directly above the marking (parallax error).
32. How can you measure the height of a very tall tree?
Answer:
Using a measuring tape plus shadow method or by marking and measuring with reference objects.
33. Why do tailors prefer flexible tapes to measure body sizes?
Answer:
Because the tape bends easily around curved parts of the body.
34. How does using thread help in measuring curved objects?
Answer:
Thread takes the exact shape of the curve; when straightened and measured, it gives accurate length.
G. DIAGRAM-BASED (TEXT-BASED) QUESTIONS
35. In Fig. 5.6, the scale starts at 1.0 cm and ends at 10.4 cm. What is the length of the object?
Answer:
10.4 – 1.0 = 9.4 cm.
36. What type of motion is shown in Fig. 5.16 (hanging eraser swinging)?
Answer:
Oscillatory motion.
37. What type of motion does a merry-go-round show?
Answer:
Circular motion.
38. Identify the motion of a child on a swing in Fig. 5.18.
Answer:
Oscillatory motion.
H. CASE STUDY QUESTIONS
39. Case: Deepa sees kilometre stones showing ‘Delhi 70 km’, then ‘Delhi 60 km’.
(a) What do these stones represent?
(b) What is the reference point?
(c) Is her position changing?
Answer:
(a) Distance from Delhi.
(b) Delhi.
(c) Yes, the distance is decreasing, showing she is moving.
40. Case: Five students measure a table using handspan but results differ.
(a) Why do results differ?
(b) What is the solution?
Answer:
(a) Handspan sizes differ.
(b) Use a standard unit like metre scale.
I. EXTRA HIGH-LEVEL QUESTIONS
41. Why are both circular and oscillatory motions considered periodic?
Answer:
Because both repeat their motions at regular time intervals.
42. A bus moves but a book on a seat seems still. Explain scientifically.
Answer:
Relative to the bus (reference point), the book’s position does not change; hence, it is at rest.
43. Why is it not advisable to measure length of a pencil using a cloth tape?
Answer:
Cloth tape bends and may not lie straight, causing inaccurate readings.
J. EXTRA EXAM-FOCUSED LONG QUESTIONS
44. Describe how you would accurately measure the length of your classroom.
Answer:
- Use a long measuring tape.
- Place it straight along the length.
- Ensure tape does not sag.
- Keep eye exactly above reading.
- Note length including unit.
- Repeat for verification.
45. Explain with reasons:
(a) Why does the girth of a tree need flexible tape?
(b) Why do we not use kilometre for measuring a pencil?
(c) Why must there be space between number and unit?
Answer:
(a) Because tree trunk is round.
(b) Kilometre is too large a unit; pencil is small.
(c) To avoid confusion between number and symbol.