Unit Test (Solution): Measurement of Length and Motion | Science for Class 6 PDF Download

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Attempt all questions. Time: 1 hour, M.M. 30

• Question numbers 1 to 7 carry 1 mark each.
• Question numbers 8 to 12 carry 2 mark each.
• Question numbers  13 to 15 carry 3 marks each.
• Question number 16 carries 4 mark each

Q1: Which of the following is the standard unit of length in the International System of Units (SI)? (1 Mark)
A) Foot
B) Inch
C) Meter
D) Yard

Ans: C) Metre

The standard unit of length in the International System of Units (SI) is the metre, denoted as 'm'.

Q2: What instrument is used to measure the length of curved objects? (1 Mark)

Ans: A flexible measuring tape is used to measure the length of curved objects accurately. 

Q3: The SI unit of length is __________. (1 Mark)

Ans: metre

The SI unit of length is the metre, which is the standard unit used in the International System of Units (SI).

Q4: What is the disadvantage of using body parts like handspan or foot for measurement? (1 Mark)
A) Measurements vary from person to person
B) It is quick
C) It is accurate for everyone
D) It is used only for large measurements

Ans: A) Measurements vary from person to person

Using body parts for measurement can lead to inconsistencies, as different people have different sizes.

Q5: What is the motion of an object called when it moves along a circular path? (1 Mark)

Ans: When an object moves along a circular path, its motion is called circular motion.

Q6: When is an object said to be in motion? (1 Mark)

Ans: An object is said to be in motion if its position changes with respect to a reference point over time.

Q7: The smallest unit of length that can be measured using a 15-cm scale is __________. (1 Mark)

Ans: centimetre

A 15-cm scale can measure lengths down to the centimetre, which is the smallest unit typically marked on such scales.

Q8: Give two examples of circular motion. (2 Mark)

Ans: Examples are as follows:

• A wheel rotating – The wheel moves around its central axis in a circular path.
• The Earth revolving around the Sun – The Earth follows a nearly circular orbit around the Sun due to gravitational force.

Q9: How should a scale be used to accurately measure length? (2 Mark)

Ans: To measure length accurately with a scale, align one end of the object with the zero mark of the scale and ensure the scale is straight. Read the measurement at the other end of the object, taking care to note the unit of measurement.

Q10: Why is using standard units of measurement important? (2 Mark)

Ans: Standard units of measurement ensure consistency and clarity in communication. They allow for accurate comparisons and calculations across different contexts and disciplines.

Q11: Compare linear motion and oscillatory motion, providing examples for each. (2 Mark)

Ans: Linear motion refers to movement in a straight line, such as a car driving on a road. Oscillatory motion involves back-and-forth movement around a central point, like a pendulum swinging. Both types of motion are fundamental in physics.

Q12: How would you measure the length of a curved line? Explain the method used. (2 Mark)

Ans: To measure the length of a curved line, you can use a flexible measuring tape, string, or thread. Place the tape or thread along the curve, ensuring it follows the shape of the line. Once the tape or thread is in place, remove it and measure its straight length using a ruler or metre scale. This method accurately captures the curved length by following its shape, making it ideal for measuring irregular or curved objects.

Q13. How the measurements using body parts to measure length were considered inconsistent?  (3 Mark)
Ans: Using body parts to measure length is often inconsistent for several reasons: Different individuals have varying sizes of body parts, such as handspans, foot spans, and strides. 
For example, one person's handspan may be longer than another's, leading to different measurements. This variability highlights the need for standard units of measurement.

Q14: How does the reference point help in determining whether an object is in motion or at rest? Provide an example. (3 Mark)

Ans: A reference point is an object or location used to describe the position of another object. If the position of the object changes with respect to this reference point over time, it is in motion. 

For example, if a person is sitting in a bus, they are at rest relative to the bus, but in motion relative to the outside world (like buildings and trees).

Q15: Define motion. What are different types of motion?  (3 Mark)
Ans: Motion is the process of changing position or moving from one place to another. The different types of motion include: 
Translational motion: Movement in the same direction covering equal distances over time. 
Linear motion: Movement along a straight line. 
Circular motion: Movement along a circular path. 
Rotational motion: Movement around an axis. 
Periodic motion: Movement to and fro about a fixed point. 

Q16: How do different measuring instruments (e.g., metre scale, measuring tape, and thread) help in measuring various objects accurately? Explain with examples of when each instrument would be used. (4 Mark)

Ans: Different measuring instruments are suited for measuring objects of various shapes and sizes. 
A metre scale is ideal for measuring straight objects like the length of a pencil or a desk, where accuracy is needed in a fixed straight line. 
A measuring tape is flexible and used for measuring larger, flexible, or irregular-shaped objects, such as the height of a room or the circumference of a tree. 
A thread is often used to measure the length of curved objects like the base of a bottle or a curved table, as it can easily follow the shape of the curve. Each instrument helps ensure accurate measurement depending on the nature of the object being measured.