Q1. What was the primary purpose of the wheel’s invention in transportation?
a) To increase the speed of travel
b) To facilitate air travel
c) To improve the efficiency of pulling loads
d) To navigate water routes more effectively
Answer: c) To improve the efficiency of pulling loads
Explanation: The invention of the wheel significantly changed modes of transport. It made it easier and more efficient to pull loads over land, improving transportation of goods and people.
Q2. How did the introduction of the steam engine revolutionize transportation in the 19th century?
a) It enabled faster water transportation
b) It led to the development of the railroad system
c) It was primarily used in aeroplanes
d) It was used to improve animal-drawn carriages
Answer: b) It led to the development of the railroad system
Explanation: The invention of the steam engine in the 19th century introduced a new source of power and led to the development of the railroad system. This marked a significant leap in land transportation.
Q3. What is the SI unit of length?
a) Inch
b) Foot
c) Centimeter
d) Meter
Answer: d) Meter
Explanation: The International System of Units (SI) specifies the meter as the unit of length. This is a standard unit used globally for scientific and general measurement.
Q4. Which of these is a standard unit of measurement?
a) The width of a finger
b) The distance of a step
c) Kilometer
d) The length of a foot
Answer: c) Kilometer
Explanation: Among the options provided, kilometer is a standard unit of measurement. It is commonly used for measuring large distances and is part of the International System of Units (SI).
Q5. What type of motion does the Earth exhibit as it orbits the Sun?
a) Rectilinear motion
b) Circular motion
c) Periodic motion
d) Random motion
Answer: c) Periodic motion
Explanation: The Earth’s orbit around the Sun is an example of periodic motion, as it repeats its path in a fixed interval of time (one year).
Q6. Why is a meter scale not suitable for measuring the girth of a tree?
a) Because it is not flexible
b) Because it is too long
c) Because it is not accurate enough
d) Because it is usually made of metal
Answer: a) Because it is not flexible
Explanation: A meter scale is rigid and not suitable for measuring curved surfaces like the girth of a tree. A measuring tape, which is flexible, would be more appropriate for this purpose.
Q7. In the experiment of measuring a desk with gilli and danda, what problem did Paheli and Boojho face?
a) The desk was too large
b) The gilli and danda were not uniform in size
c) The desk was of irregular shape
d) The gilli and danda were too short
Answer: b) The gilli and danda were not uniform in size
Explanation: Paheli and Boojho faced the issue of inconsistency in the size of gilli and danda. When Boojho used a new set, the measurements differed, highlighting the need for a standard unit of measurement.
Q8. Which of these is an example of circular motion?
a) A horse running in a straight line
b) A car moving on a straight road
c) A stone tied to a string and whirled around
d) A train moving on straight tracks
Answer: c) A stone tied to a string and whirled around
Explanation: A stone tied to a string and whirled around exhibits circular motion. In this motion, the stone moves along a circular path with its distance from the hand (center) remaining constant.
Q9. What is the significance of using a standard unit of measurement?
a) It allows for more accurate measurements
b) It ensures consistency and uniformity in measurements
c) It is easier to use than non-standard units
d) It can measure any type of distance or length
Answer: b) It ensures consistency and uniformity in measurements
Explanation: Using a standard unit of measurement ensures consistency and uniformity, which is essential for clear communication and comparison of measurements. Without standard units, measurements could vary significantly from person to person.
Q10. Why is a measuring tape more suitable than a meter scale for measuring the girth of a tree?
a) Because it is longer than a meter scale
b) Because it can measure curved surfaces accurately
c) Because it is more durable than a meter scale
d) Because it has units in both meters and feet
Answer: b) Because it can measure curved surfaces accurately
Explanation: A measuring tape is flexible and can wrap around curved surfaces like the girth of a tree, providing an accurate measurement. In contrast, a rigid meter scale cannot conform to curved surfaces.
Q11. What does the length of 1 kilometer equal in meters?
a) 100 meters
b) 1,000 meters
c) 10,000 meters
d) 100,000 meters
Answer: b) 1,000 meters
Explanation: One kilometer is equal to 1,000 meters. The kilometer is a larger unit of length used for measuring long distances and is a part of the International System of Units (SI).
Q12. What type of motion is exhibited by the hands of a clock?
a) Rectilinear motion
b) Random motion
c) Circular motion
d) Periodic motion
Answer: c) Circular motion
Explanation: The hands of a clock exhibit circular motion as they move in a circular path around the clock face. The distance of the hands from the center of the clock (pivot point) remains constant as they rotate.
Q13. Which of these examples demonstrates periodic motion?
a) A car moving down a straight road
b) The Earth revolving around the Sun
c) A boat sailing in a straight line
d) A bird flying in the sky
Answer: b) The Earth revolving around the Sun
Explanation: The Earth’s revolution around the Sun is an example of periodic motion, as it completes its orbit in a fixed time period (one year). Periodic motion involves repetitive movement in a regular time interval.
Q14. What is the primary reason for measuring the length of a curved line using a thread?
a) A thread can be stretched
b) A thread is easier to handle
c) A thread can take the shape of the curve
d) A thread is more accurate than a ruler
Answer: c) A thread can take the shape of the curve
Explanation: A thread is flexible and can easily take the shape of a curved line, allowing for an accurate measurement of its length. Rigid measuring devices like rulers or meter scales cannot bend to follow the curve.
Q15. In the context of the chapter, why is it important to have the correct position of the eye while taking a measurement?
a) To avoid errors due to parallax
b) To reduce the strain on the eyes
c) To ensure the scale is straight
d) To get a better view of the object
Answer: a) To avoid errors due to parallax
Explanation: The correct position of the eye (directly above the point of measurement) is important to avoid parallax errors. Parallax errors occur when the measurement is taken from an angle, leading to inaccurate readings.
Q16. How did the development of motorized boats impact transportation?
a) It increased the speed of air travel
b) It allowed for longer journeys on water
c) It eliminated the need for water transport
d) It reduced the efficiency of water transportation
Answer: b) It allowed for longer journeys on water
Explanation: The development of motorized boats and ships significantly enhanced water transportation. They allowed for longer and faster journeys on water, improving trade and travel across seas and oceans.
Q17. What was a significant change in transportation brought about by the invention of the steam engine?
a) Introduction of air travel
b) Development of automobiles
c) Invention of bicycles
d) Advancement of rail transport
Answer: d) Advancement of rail transport
Explanation: The invention of the steam engine in the 19th century led to the significant advancement of rail transport. Steam engines were the driving force behind the early railroads, revolutionizing land transportation.
Q18. Which of these is a disadvantage of using body parts as units of measurement?
a) They are too large for small measurements.
b) They change with age and person.
c) They are not available everywhere.
d) They can only measure straight lines.
Answer: b) They change with age and person.
Explanation: Using body parts as units of measurement is unreliable because the size of these parts varies from person to person and can change with age. This variability leads to inconsistency in measurements.
Q19. What is the primary purpose of dividing a meter into 100 centimeters and each centimeter into 10 millimeters?
a) To make the meter longer
b) To ensure greater accuracy in measurement
c) To make calculations easier
d) To align with the decimal system
Answer: b) To ensure greater accuracy in measurement
Explanation: Dividing a meter into 100 centimeters and each centimeter into 10 millimeters allows for greater precision and accuracy in measurement. Smaller divisions enable more detailed and exact measurements.
Q20. What kind of motion is demonstrated by a sewing machine’s needle?
a) Circular motion
b) Rectilinear motion
c) Periodic motion
d) Random motion
Answer: c) Periodic motion
Explanation: The needle of a sewing machine demonstrates periodic motion. It moves up and down in a regular and repeated manner, following a specific rhythm as long as the machine is operating.
Q21. In the context of the chapter, why is it important to measure distances?
a) To determine the weight of objects
b) To calculate the time taken to travel
c) To plan and determine the mode of transportation
d) To understand the shape of objects
Answer: c) To plan and determine the mode of transportation
Explanation: Knowing the distance between places is crucial for planning journeys and determining the most suitable mode of transportation, whether it’s walking, driving, or taking public transport.
Q22. Which of the following is an example of rectilinear motion?
a) A bird flying in the sky
b) A car driving along a straight road
c) A child swinging in a park
d) The Earth orbiting the Sun
Answer: b) A car driving along a straight road
Explanation: Rectilinear motion refers to motion in a straight line. A car driving along a straight road is an example of rectilinear motion, as it moves in a single direction without changing its path.
Q23. Why is it not feasible to use elastic measuring tapes for precise measurements?
a) They can stretch and give inaccurate results
b) They are not long enough
c) They are difficult to handle
d) They do not have standard units
Answer: a) They can stretch and give inaccurate results
Explanation: Elastic measuring tapes are not suitable for precise measurements because they can stretch, leading to variations and inaccuracies in the measured length.
Q24. What does the distance of one kilometer equate to in meters?
a) 100 meters
b) 1,000 meters
c) 10,000 meters
d) 100,000 meters
Answer: b) 1,000 meters
Explanation: One kilometer is equivalent to 1,000 meters. This conversion is part of the metric system, where ‘kilo-‘ denotes a thousandfold increase in the base unit, in this case, the meter.
Q25. What did people in ancient India use as small length measurements?
a) Meter and centimeter
b) Foot and yard
c) Angul (finger) and mutthi (fist)
d) Kilometer and meter
Answer: c) Angul (finger) and mutthi (fist)
Explanation: In ancient India, people used body parts as units of measurement for small lengths. An ‘angul’ referred to the width of a finger, and a ‘mutthi’ referred to a fist. These were common units before the standardization of measurements.
Q26. How does the metric system ensure uniformity in measurement?
a) By using body parts as standard units
b) By using variable units based on the object size
c) By adopting a universal standard of units
d) By allowing different regions to use their local units
Answer: c) By adopting a universal standard of units
Explanation: The metric system ensures uniformity in measurement by adopting a universal standard of units, like meters, liters, and grams. This system is widely accepted across the world and provides a consistent method for measuring various quantities.
Q27. What type of motion is exhibited by the blades of a fan?
a) Periodic motion
b) Circular motion
c) Rectilinear motion
d) Oscillatory motion
Answer: b) Circular motion
Explanation: The blades of a fan exhibit circular motion. They rotate around a fixed point (the center of the fan), maintaining a constant distance from this point, which characterizes circular motion.
Q28. Which of the following best describes a cubit?
a) A unit of length based on the width of a hand
b) A unit of length based on the distance of a step
c) A unit of length from the elbow to the fingertips
d) A unit of length based on the length of a foot
Answer: c) A unit of length from the elbow to the fingertips
Explanation: A cubit is an ancient unit of length that was typically based on the length from the elbow to the fingertips. It was used in ancient Egypt and other cultures as a measurement unit.
Q29. For measuring large distances, which unit is more convenient than the meter?
a) Millimeter
b) Centimeter
c) Kilometer
d) Inch
Answer: c) Kilometer
Explanation: For measuring large distances, the kilometer is more convenient than the meter. One kilometer equals 1,000 meters, making it a suitable unit for measuring distances between cities, geographical features, and in various astronomical contexts.
Q30. What is the main advantage of using a standard scale for measurement?
a) It provides measurements in multiple units
b) It is more durable than non-standard scales
c) It ensures uniformity and comparability of measurements
d) It automatically adjusts to the size of the object being measured
Answer: c) It ensures uniformity and comparability of measurements
Explanation: The main advantage of using a standard scale is that it ensures uniformity and comparability of measurements. With a standard scale, measurements are consistent and can be reliably compared across different contexts and users.
Q31. What does the periodic motion of a pendulum illustrate?
a) The motion is always in a straight line
b) The motion repeats after a fixed interval of time
c) The motion is independent of gravitational force
d) The motion occurs only in one direction
Answer: b) The motion repeats after a fixed interval of time
Explanation: The periodic motion of a pendulum illustrates that the motion repeats itself after a fixed interval of time. The pendulum swings back and forth in a regular, repeated pattern, characteristic of periodic motion.
Q32. Why is a standard unit of length important in scientific and everyday measurements?
a) It allows for the use of complex equipment
b) It facilitates trade and commerce internationally
c) It makes measurements easy to remember
d) It ensures consistency and reliability in measurements
Answer: d) It ensures consistency and reliability in measurements
Explanation: A standard unit of length is crucial in scientific and everyday measurements because it ensures consistency and reliability. With a standard unit, measurements can be accurately communicated and compared across different regions and contexts.
Q33. Why was the length of a foot considered an unreliable unit of measurement?
a) It varied with the person’s age.
b) It was too short for practical use.
c) It differed from person to person.
d) It was not a straight-line measurement.
Answer: c) It differed from person to person.
Explanation: The length of a foot as a unit of measurement was considered unreliable because it varied significantly from person to person. Different individuals have different foot sizes, leading to inconsistency in measurements.
Q34. What is the primary function of the International System of Units (SI)?
a) To provide a set of units for astronomical measurements only
b) To establish a common standard for scientific measurements
c) To replace all traditional units of measurement
d) To standardize units for chemical experiments only
Answer: b) To establish a common standard for scientific measurements
Explanation: The International System of Units (SI) was established to create a common standard for scientific measurements worldwide. This system ensures consistency and universal understanding in measurements across various scientific disciplines.
Q35. Which activity demonstrates the concept of measuring the length of a curved line?
a) Using a ruler to measure the edge of a book
b) Using a thread to measure the length of a river on a map
c) Measuring the height of a building with a measuring tape
d) Using a scale to measure the diameter of a circular track
Answer: b) Using a thread to measure the length of a river on a map
Explanation: Using a thread to measure the length of a river on a map is an effective way to measure the length of a curved line. The thread can be laid along the curved path of the river, accurately tracing its bends and turns.
Q36. What kind of motion is observed when an object moves along a straight line?
a) Circular motion
b) Periodic motion
c) Rectilinear motion
d) Oscillatory motion
Answer: c) Rectilinear motion
Explanation: Rectilinear motion is observed when an object moves along a straight line. This type of motion is characterized by movement in one direction along a single straight path.
Q37. How did the use of animals in ancient transportation methods enhance mobility?
a) By providing a faster mode of air travel
b) By allowing people to carry heavier loads over longer distances
c) By enabling underwater transportation
d) By facilitating communication through signaling
Answer: b) By allowing people to carry heavier loads over longer distances
Explanation: In ancient times, the use of animals in transportation significantly enhanced mobility by enabling people to carry heavier loads over longer distances than they could manage on foot. Animals like horses, oxen, and camels were commonly used for this purpose.
Q38. What is the purpose of dividing the string into smaller units in measuring length?
a) To make the string more flexible
b) To increase the accuracy of measurements
c) To make the string longer
d) To demonstrate the concept of elasticity
Answer: b) To increase the accuracy of measurements
Explanation: Dividing the string into smaller units, such as halves or quarters, increases the accuracy of measurements, especially when measuring lengths shorter than the full length of the string.
Q39. What is a common characteristic of objects undergoing circular motion?
a) Their speed constantly changes.
b) They follow a straight-line path.
c) Their distance from a fixed point remains constant.
d) They always move downward due to gravity.
Answer: c) Their distance from a fixed point remains constant.
Explanation: A common characteristic of objects undergoing circular motion is that their distance from a fixed central point remains constant. This is true for objects like the blades of a fan or a planet orbiting a star.
Q40. Why is measuring the height of a person with a tape measure more accurate than using hand spans?
a) Because a tape measure is longer than a hand span
b) Because a tape measure is based on standard units
c) Because hand spans vary from person to person
d) Because a tape measure is more flexible
Answer: c) Because hand spans vary from person to person
Explanation: Measuring the height of a person with a tape measure is more accurate than using hand spans because hand spans can vary significantly between different individuals. A tape measure provides a standard unit of measurement, ensuring consistency and accuracy.