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201. Which instrument is used to measure the dimensions and profiles of microstructures with high precision and depth resolution?
ⓐ. Atomic force microscope
ⓑ. Scanning electron microscope
ⓒ. Laser interferometer
ⓓ. Scanning tunneling microscope
Correct Answer: Scanning electron microscope
Explanation: A scanning electron microscope is used to measure the dimensions and profiles of microstructures with high precision and depth resolution by scanning a focused beam of electrons over the sample surface.
202. Which instrument is used to measure the force interactions between a sharp probe and a material’s surface at the nanoscale?
ⓐ. Laser interferometer
ⓑ. Scanning tunneling microscope
ⓒ. Atomic force microscope
ⓓ. Electron microscope
Correct Answer: Atomic force microscope
Explanation: An atomic force microscope measures force interactions between a sharp probe and a material’s surface at the nanoscale by scanning the probe over the surface and detecting atomic forces.
203. Which instrument is used to measure the distance changes in an interferometer setup using laser light interference patterns?
ⓐ. Scanning electron microscope
ⓑ. Atomic force microscope
ⓒ. Scanning tunneling microscope
ⓓ. Laser interferometer
Correct Answer: Laser interferometer
Explanation: A laser interferometer measures distance changes in an interferometer setup using laser light interference patterns, providing highly accurate length measurements.
204. Which instrument is used to observe and measure the surface topography and properties of materials at atomic and molecular levels?
ⓐ. Scanning tunneling microscope
ⓑ. Scanning electron microscope
ⓒ. Atomic force microscope
ⓓ. Laser interferometer
Correct Answer: Scanning tunneling microscope
Explanation: A scanning tunneling microscope observes and measures the surface topography and properties of materials at atomic and molecular levels by scanning a sharp tip close to the surface and measuring tunneling current.
205. Which instrument is used to produce detailed images and measure the dimensions of microstructures by scanning a beam of electrons?
ⓐ. Atomic force microscope
ⓑ. Scanning electron microscope
ⓒ. Scanning tunneling microscope
ⓓ. Laser interferometer
Correct Answer: Scanning electron microscope
Explanation: A scanning electron microscope produces detailed images and measures the dimensions of microstructures by scanning a beam of electrons over the sample surface.
206. Which instrument is used to measure the exact distances and dimensions of nanoscale structures by detecting atomic forces?
ⓐ. Scanning tunneling microscope
ⓑ. Laser interferometer
ⓒ. Atomic force microscope
ⓓ. Scanning electron microscope
Correct Answer: Atomic force microscope
Explanation: An atomic force microscope measures exact distances and dimensions of nanoscale structures by detecting atomic forces between a sharp probe and the sample surface.
207. Which instrument is used to measure the heights and depths of microstructures with high precision and resolution?
ⓐ. Scanning electron microscope
ⓑ. Laser interferometer
ⓒ. Atomic force microscope
ⓓ. Scanning tunneling microscope
Correct Answer: Scanning electron microscope
Explanation: A scanning electron microscope measures the heights and depths of microstructures with high precision and resolution by scanning a focused beam of electrons over the sample surface.
208. Which instrument is used to investigate the topography and properties of materials at sub-nanometer scales?
ⓐ. Laser interferometer
ⓑ. Atomic force microscope
ⓒ. Scanning electron microscope
ⓓ. Scanning tunneling microscope
Correct Answer: Scanning tunneling microscope
Explanation: A scanning tunneling microscope investigates the topography and properties of materials at sub-nanometer scales by scanning a sharp tip close to the surface and measuring tunneling current.
209. Which instrument is used to measure the distance changes in an interferometer setup to monitor microscopic movements and vibrations?
ⓐ. Scanning tunneling microscope
ⓑ. Laser interferometer
ⓒ. Atomic force microscope
ⓓ. Scanning electron microscope
Correct Answer: Laser interferometer
Explanation: A laser interferometer measures distance changes in an interferometer setup to monitor microscopic movements and vibrations using laser light interference patterns.
210. Which instrument is used to measure the atomic-scale interactions and properties of materials by scanning a sharp tip across the sample surface?
ⓐ. Scanning electron microscope
ⓑ. Scanning tunneling microscope
ⓒ. Atomic force microscope
ⓓ. Laser interferometer
Correct Answer: Scanning tunneling microscope
Explanation: A scanning tunneling microscope measures atomic-scale interactions and properties of materials by scanning a sharp tip across the sample surface and detecting tunneling current variations.
211. What is the fundamental unit of mass in the International System of Units (SI)?
ⓐ. Gram
ⓑ. Kilogram
ⓒ. Milligram
ⓓ. Metric ton
Correct Answer: Kilogram
Explanation: The kilogram is the fundamental unit of mass in the International System of Units (SI), defined as the mass of the international prototype of the kilogram.
212. Which unit of mass is equal to 1000 grams?
ⓐ. Gram
ⓑ. Kilogram
ⓒ. Milligram
ⓓ. Metric ton
Correct Answer: Kilogram
Explanation: A kilogram is equal to 1000 grams. It is the base unit of mass in the SI system.
213. Which unit of mass is commonly used for measuring large quantities, such as the weight of vehicles and goods?
ⓐ. Kilogram
ⓑ. Gram
ⓒ. Metric ton
ⓓ. Milligram
Correct Answer: Metric ton
Explanation: A metric ton, also known as a tonne, is commonly used for measuring large quantities of mass, equal to 1000 kilograms or approximately 2204.62 pounds.
214. Which unit of mass is equal to one-thousandth of a gram?
ⓐ. Milligram
ⓑ. Gram
ⓒ. Kilogram
ⓓ. Metric ton
Correct Answer: Milligram
Explanation: A milligram is equal to one-thousandth of a gram. It is used for measuring very small masses, such as in pharmaceuticals and chemistry.
215. Which unit of mass is often used for expressing the weight of small items like jewelry and precious metals?
ⓐ. Metric ton
ⓑ. Kilogram
ⓒ. Milligram
ⓓ. Gram
Correct Answer: Gram
Explanation: The gram is often used for expressing the weight of small items like jewelry and precious metals, as well as in everyday measurements.
216. Which unit of mass is approximately equal to 2.2046 pounds?
ⓐ. Metric ton
ⓑ. Gram
ⓒ. Kilogram
ⓓ. Milligram
Correct Answer: Kilogram
Explanation: A kilogram is approximately equal to 2.2046 pounds. It is widely used as the standard unit of mass in most countries around the world.
217. Which unit of mass is used in scientific research and precise measurements due to its stability and reproducibility?
ⓐ. Metric ton
ⓑ. Kilogram
ⓒ. Gram
ⓓ. Milligram
Correct Answer: Kilogram
Explanation: The kilogram is used in scientific research and precise measurements due to its stability and reproducibility as the base unit of mass in the SI system.
218. Which unit of mass is often used in daily life for measuring the weight of food items and personal objects?
ⓐ. Gram
ⓑ. Milligram
ⓒ. Kilogram
ⓓ. Metric ton
Correct Answer: Kilogram
Explanation: The kilogram is often used in daily life for measuring the weight of food items, personal objects, and other everyday goods.
219. Which unit of mass is equal to 1000 kilograms?
ⓐ. Metric ton
ⓑ. Gram
ⓒ. Milligram
ⓓ. Kilogram
Correct Answer: Metric ton
Explanation: A metric ton, or tonne, is equal to 1000 kilograms. It is commonly used in industries such as agriculture, shipping, and manufacturing.
220. Which unit of mass is suitable for measuring the weight of very small quantities, such as the active ingredients in medications?
ⓐ. Kilogram
ⓑ. Gram
ⓒ. Milligram
ⓓ. Metric ton
Correct Answer: Milligram
Explanation: The milligram is suitable for measuring the weight of very small quantities, such as the active ingredients in medications and supplements.
221. Which unit of mass is commonly used for expressing the weight of large objects such as trucks and heavy machinery?
ⓐ. Gram
ⓑ. Kilogram
ⓒ. Metric ton
ⓓ. Milligram
Correct Answer: Metric ton
Explanation: A metric ton (tonne) is commonly used for expressing the weight of large objects such as trucks and heavy machinery, equivalent to 1000 kilograms.
222. Which unit of mass is equivalent to \(10^{6}\) grams?
ⓐ. Megagram
ⓑ. Kilogram
ⓒ. Milligram
ⓓ. Metric ton
Correct Answer: Megagram
Explanation: A megagram, also known as a metric tonne or tonne, is equivalent to \(10^{6}\) grams or 1000 kilograms.
223. Which unit of mass is often used for scientific measurements and calculations involving very small quantities, such as in chemistry and physics?
ⓐ. Gram
ⓑ. Milligram
ⓒ. Kilogram
ⓓ. Metric ton
Correct Answer: Milligram
Explanation: The milligram is often used for scientific measurements and calculations involving very small quantities, particularly in chemistry and physics.
224. Which unit of mass is the base unit for measuring mass in the International System of Units (SI)?
ⓐ. Kilogram
ⓑ. Gram
ⓒ. Milligram
ⓓ. Metric ton
Correct Answer: Kilogram
Explanation: The kilogram is the base unit for measuring mass in the International System of Units (SI), defined as the mass of the international prototype of the kilogram.
225. Which unit of mass is commonly used for measuring the weight of food items and ingredients in recipes?
ⓐ. Metric ton
ⓑ. Gram
ⓒ. Kilogram
ⓓ. Milligram
Correct Answer: Gram
Explanation: The gram is commonly used for measuring the weight of food items and ingredients in recipes due to its convenient size for small quantities.
226. Which unit of mass is equal to one-thousandth of a kilogram?
ⓐ. Milligram
ⓑ. Gram
ⓒ. Metric ton
ⓓ. Megagram
Correct Answer: Milligram
Explanation: A milligram is equal to one-thousandth of a kilogram, making it suitable for measuring very small masses.
227. Which unit of mass is often used in manufacturing and commerce for bulk goods such as grains and metals?
ⓐ. Gram
ⓑ. Metric ton
ⓒ. Milligram
ⓓ. Kilogram
Correct Answer: Metric ton
Explanation: The metric ton (tonne) is often used in manufacturing and commerce for bulk goods such as grains and metals, where larger quantities are measured.
228. Which unit of mass is commonly used in pharmaceuticals and medicine for measuring precise dosages of drugs?
ⓐ. Kilogram
ⓑ. Milligram
ⓒ. Gram
ⓓ. Metric ton
Correct Answer: Milligram
Explanation: The milligram is commonly used in pharmaceuticals and medicine for measuring precise dosages of drugs and supplements.
229. Which unit of mass is used for expressing the weight of small objects and personal items?
ⓐ. Metric ton
ⓑ. Gram
ⓒ. Milligram
ⓓ. Kilogram
Correct Answer: Kilogram
Explanation: The kilogram is used for expressing the weight of small objects and personal items in daily life and everyday measurements.
230. Which unit of mass is equivalent to 1000 milligrams?
ⓐ. Kilogram
ⓑ. Metric ton
ⓒ. Gram
ⓓ. Megagram
Correct Answer: Gram
Explanation: A gram is equivalent to 1000 milligrams, making it a convenient unit for small-scale measurements and scientific applications.
231. Which instrument measures the mass of an object by comparing it to known masses on two pans?
ⓐ. Electronic balance
ⓑ. Triple beam balance
ⓒ. Spring balance
ⓓ. Digital scale
Correct Answer: Triple beam balance
Explanation: A triple beam balance measures the mass of an object by comparing it to known masses on two pans, using sliding weights for precise measurement.
232. Which instrument measures the mass of an object by applying the principle of Hooke’s law?
ⓐ. Electronic balance
ⓑ. Triple beam balance
ⓒ. Spring balance
ⓓ. Digital scale
Correct Answer: Spring balance
Explanation: A spring balance measures the mass of an object by applying the principle of Hooke’s law, which relates the force exerted by a spring to the displacement of its end.
233. Which instrument measures the mass of an object electronically using a load cell and a digital display?
ⓐ. Triple beam balance
ⓑ. Spring balance
ⓒ. Electronic balance
ⓓ. Digital scale
Correct Answer: Electronic balance
Explanation: An electronic balance measures the mass of an object electronically using a load cell and a digital display, providing accurate and quick measurements.
234. Which instrument measures the mass of an object by converting the force of gravity acting on it into an electrical signal?
ⓐ. Digital scale
ⓑ. Electronic balance
ⓒ. Triple beam balance
ⓓ. Spring balance
Correct Answer: Digital scale
Explanation: A digital scale measures the mass of an object by converting the force of gravity acting on it into an electrical signal, displayed digitally for easy reading.
235. Which instrument is commonly used in laboratories and industries for precise measurement of mass?
ⓐ. Spring balance
ⓑ. Digital scale
ⓒ. Triple beam balance
ⓓ. Electronic balance
Correct Answer: Electronic balance
Explanation: An electronic balance is commonly used in laboratories and industries for precise measurement of mass, offering accuracy and ease of use.
236. Which instrument measures the mass of an object by suspending it from a hook and reading the extension of a spring?
ⓐ. Digital scale
ⓑ. Triple beam balance
ⓒ. Electronic balance
ⓓ. Spring balance
Correct Answer: Spring balance
Explanation: A spring balance measures the mass of an object by suspending it from a hook and reading the extension of a spring, calibrated to indicate mass directly.
237. Which instrument measures the mass of an object using a beam with sliding weights on calibrated scales?
ⓐ. Electronic balance
ⓑ. Triple beam balance
ⓒ. Digital scale
ⓓ. Spring balance
Correct Answer: Triple beam balance
Explanation: A triple beam balance measures the mass of an object using a beam with sliding weights on calibrated scales, providing precise measurements.
238. Which instrument is suitable for measuring the mass of objects ranging from small items to large quantities with high accuracy?
ⓐ. Spring balance
ⓑ. Digital scale
ⓒ. Electronic balance
ⓓ. Triple beam balance
Correct Answer: Electronic balance
Explanation: An electronic balance is suitable for measuring the mass of objects ranging from small items to large quantities with high accuracy and efficiency.
239. Which instrument provides measurements of mass quickly and accurately, displaying results digitally?
ⓐ. Spring balance
ⓑ. Digital scale
ⓒ. Triple beam balance
ⓓ. Electronic balance
Correct Answer: Digital scale
Explanation: A digital scale provides measurements of mass quickly and accurately, displaying results digitally for easy reading and recording.
240. Which instrument is preferred for measuring mass in educational settings due to its simple operation and clear visual indication?
ⓐ. Electronic balance
ⓑ. Triple beam balance
ⓒ. Spring balance
ⓓ. Digital scale
Correct Answer: Triple beam balance
Explanation: A triple beam balance is preferred for measuring mass in educational settings due to its simple operation and clear visual indication of measurement.
241. What is the fundamental difference between weight and mass?
ⓐ. Weight is a measure of the amount of matter in an object, while mass is the gravitational force acting on an object.
ⓑ. Mass is a measure of the amount of matter in an object, while weight is the gravitational force acting on an object.
ⓒ. Weight is measured in grams, while mass is measured in kilograms.
ⓓ. Mass is measured using a spring balance, while weight is measured using an electronic balance.
Correct Answer: Mass is a measure of the amount of matter in an object, while weight is the gravitational force acting on an object.
Explanation: Mass is a scalar quantity that measures the amount of matter in an object, whereas weight is a vector quantity that measures the gravitational force acting on an object.
242. Which property of an object remains the same regardless of its location in the universe?
ⓐ. Mass
ⓑ. Weight
ⓒ. Volume
ⓓ. Density
Correct Answer: Mass
Explanation: Mass is an intrinsic property of an object that remains constant regardless of its location in the universe, whereas weight varies depending on the gravitational pull at different locations.
243. On which planet would the weight of an object be the highest compared to its mass on Earth?
ⓐ. Mars
ⓑ. Venus
ⓒ. Jupiter
ⓓ. Moon
Correct Answer: Jupiter
Explanation: Weight depends on the gravitational acceleration of the planet, which varies from planet to planet. Jupiter has a much stronger gravitational pull compared to Earth, resulting in a higher weight for the same mass.
244. Which instrument is used to measure mass, independent of the gravitational field?
ⓐ. Spring balance
ⓑ. Electronic balance
ⓒ. Triple beam balance
ⓓ. Beam balance
Correct Answer: Triple beam balance
Explanation: A triple beam balance measures mass by comparing the object’s mass against known masses, independent of the gravitational field, providing an accurate measurement of mass.
245. What happens to the mass of an object when taken to the Moon from Earth?
ⓐ. Increases
ⓑ. Decreases
ⓒ. Remains the same
ⓓ. Becomes zero
Correct Answer: Remains the same
Explanation: Mass is an intrinsic property of an object and remains the same regardless of the location or gravitational field. On the Moon, an object’s mass would be the same as it is on Earth.
246. Which physical quantity is measured in kilograms or grams?
ⓐ. Weight
ⓑ. Mass
ⓒ. Volume
ⓓ. Density
Correct Answer: Mass
Explanation: Mass is measured in kilograms (kg) or grams (g) and is a measure of the amount of matter in an object, while weight is measured in newtons (N) and depends on the gravitational force acting on the object.
247. Which property of an object is influenced by gravitational force?
ⓐ. Mass
ⓑ. Weight
ⓒ. Volume
ⓓ. Density
Correct Answer: Weight
Explanation: Weight is influenced by gravitational force and varies depending on the strength of gravity at different locations, whereas mass is independent of gravitational force.
248. Which quantity is a measure of the inertia of an object?
ⓐ. Mass
ⓑ. Weight
ⓒ. Volume
ⓓ. Density
Correct Answer: Mass
Explanation: Mass is a measure of the inertia of an object, representing its resistance to acceleration when a force is applied, whereas weight is the force exerted on an object due to gravity.
249. Which property of an object is a vector quantity?
ⓐ. Mass
ⓑ. Weight
ⓒ. Volume
ⓓ. Density
Correct Answer: Weight
Explanation: Weight is a vector quantity because it has both magnitude (amount) and direction (towards the center of the gravitational field), whereas mass is a scalar quantity with only magnitude.
250. Which property of an object is used to calculate the force due to gravity?
ⓐ. Mass
ⓑ. Weight
ⓒ. Volume
ⓓ. Density
Correct Answer: Mass
Explanation: The force due to gravity is calculated using an object’s mass and the acceleration due to gravity (9.8 m/s² on Earth). Weight is the measure of this force exerted on the object.
251. Which unit of time is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of cesium-133?
ⓐ. Second
ⓑ. Minute
ⓒ. Hour
ⓓ. Day
Correct Answer: Second
Explanation: The second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of cesium-133.
252. Which unit of time is commonly used for measuring short durations, such as intervals between events?
ⓐ. Day
ⓑ. Second
ⓒ. Year
ⓓ. Month
Correct Answer: Second
Explanation: The second is commonly used for measuring short durations, such as intervals between events or the timing of processes.
253. Which unit of time is equal to 60 seconds?
ⓐ. Minute
ⓑ. Hour
ⓒ. Day
ⓓ. Week
Correct Answer: Minute
Explanation: A minute is equal to 60 seconds, commonly used for measuring shorter durations than hours.
254. Which unit of time is equal to 60 minutes?
ⓐ. Second
ⓑ. Hour
ⓒ. Day
ⓓ. Week
Correct Answer: Hour
Explanation: An hour is equal to 60 minutes, commonly used for measuring time spans in daily life and activities.
255. Which unit of time is equal to 24 hours?
ⓐ. Second
ⓑ. Minute
ⓒ. Day
ⓓ. Week
Correct Answer: Day
Explanation: A day is equal to 24 hours, representing one complete rotation of the Earth on its axis.
256. Which unit of time is approximately equal to 365.25 days?
ⓐ. Second
ⓑ. Minute
ⓒ. Year
ⓓ. Month
Correct Answer: Year
Explanation: A year is approximately equal to 365.25 days, representing one complete orbit of the Earth around the Sun.
257. Which unit of time is equal to 7 days?
ⓐ. Second
ⓑ. Minute
ⓒ. Week
ⓓ. Month
Correct Answer: Week
Explanation: A week is equal to 7 days, commonly used for organizing schedules and planning activities.
258. Which unit of time is equal to approximately 30.44 days?
ⓐ. Second
ⓑ. Minute
ⓒ. Month
ⓓ. Year
Correct Answer: Month
Explanation: A month is equal to approximately 30.44 days on average, although different months vary slightly in length.
259. Which unit of time is commonly used for geological or cosmological events spanning millions or billions of years?
ⓐ. Second
ⓑ. Minute
ⓒ. Year
ⓓ. Eon
Correct Answer: Eon
Explanation: An eon is commonly used for geological or cosmological events spanning millions or billions of years, representing vast time scales in Earth’s history.
260. Which unit of time is commonly used for measuring short intervals, such as the duration of a heartbeat?
ⓐ. Second
ⓑ. Minute
ⓒ. Hour
ⓓ. Millisecond
Correct Answer: Millisecond
Explanation: A millisecond is commonly used for measuring very short intervals of time, such as the duration of a heartbeat or the response time of electronic devices.
261. Which instrument measures elapsed time with precision down to fractions of a second?
ⓐ. Stopwatch
ⓑ. Atomic clock
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Stopwatch
Explanation: A stopwatch measures elapsed time with precision down to fractions of a second, commonly used in sports, science experiments, and various timing applications.
262. Which instrument uses the vibrations of atoms to measure time with extreme accuracy?
ⓐ. Stopwatch
ⓑ. Atomic clock
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Atomic clock
Explanation: An atomic clock uses the vibrations of atoms, typically cesium or rubidium atoms, to measure time with extreme accuracy, essential for modern technologies such as GPS and telecommunications.
263. Which instrument measures time using the position of the sun’s shadow?
ⓐ. Stopwatch
ⓑ. Atomic clock
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Sundial
Explanation: A sundial measures time using the position of the sun’s shadow cast on a calibrated dial, making it one of the oldest known timekeeping devices.
264. Which instrument measures time by the flow of sand through a narrow opening?
ⓐ. Stopwatch
ⓑ. Atomic clock
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Hourglass
Explanation: An hourglass measures time by the flow of sand or granular material through a narrow opening between two chambers, providing a visual indication of elapsed time.
265. Which instrument is suitable for measuring short durations accurately, often used in scientific experiments?
ⓐ. Atomic clock
ⓑ. Stopwatch
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Stopwatch
Explanation: A stopwatch is suitable for measuring short durations accurately, often used in scientific experiments, athletic competitions, and various timing applications.
266. Which instrument provides the most precise measurement of time among the options?
ⓐ. Hourglass
ⓑ. Sundial
ⓒ. Atomic clock
ⓓ. Stopwatch
Correct Answer: Atomic clock
Explanation: An atomic clock provides the most precise measurement of time among the options, based on the oscillations of atoms which are highly stable and predictable.
267. Which instrument is dependent on sunlight for accurate time measurement?
ⓐ. Stopwatch
ⓑ. Atomic clock
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Sundial
Explanation: A sundial is dependent on sunlight for accurate time measurement, using the position of the sun’s shadow to indicate the time of day.
268. Which instrument was historically used for measuring time at sea before modern navigation technologies?
ⓐ. Stopwatch
ⓑ. Atomic clock
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Hourglass
Explanation: An hourglass was historically used for measuring time at sea before modern navigation technologies, providing a reliable method for determining elapsed time during navigation.
269. Which instrument is used in laboratories for synchronization and precise timing of experiments?
ⓐ. Atomic clock
ⓑ. Stopwatch
ⓒ. Sundial
ⓓ. Hourglass
Correct Answer: Atomic clock
Explanation: An atomic clock is used in laboratories for synchronization and precise timing of experiments due to its high accuracy and stability.
270. Which instrument measures time intervals in milliseconds or microseconds?
ⓐ. Sundial
ⓑ. Stopwatch
ⓒ. Atomic clock
ⓓ. Hourglass
Correct Answer: Stopwatch
Explanation: A stopwatch measures time intervals in milliseconds or microseconds, providing precise timing for various applications including sports, experiments, and industrial processes.
271. Which ancient timekeeping device uses the position of the sun’s shadow to indicate time?
ⓐ. Sundial
ⓑ. Water clock
ⓒ. Candle clock
ⓓ. Sand clock
Correct Answer: Sundial
Explanation: A sundial uses the position of the sun’s shadow cast on a calibrated dial to indicate time, making it one of the earliest methods of measuring time accurately.
272. Which ancient timekeeping device uses the flow of water from one container to another to measure time intervals?
ⓐ. Sundial
ⓑ. Water clock
ⓒ. Candle clock
ⓓ. Sand clock
Correct Answer: Water clock
Explanation: A water clock, or clepsydra, measures time intervals based on the flow of water from one container to another, marking the passage of time.
273. Which historical timekeeping device uses the gradual melting of wax to measure time intervals?
ⓐ. Sundial
ⓑ. Water clock
ⓒ. Candle clock
ⓓ. Sand clock
Correct Answer: Candle clock
Explanation: A candle clock measures time intervals based on the gradual burning or melting of wax in candles, where each marked division represents a specific amount of time.
274. Which historical timekeeping device uses the flow of sand through a narrow opening to measure time intervals?
ⓐ. Sundial
ⓑ. Water clock
ⓒ. Candle clock
ⓓ. Sand clock
Correct Answer: Sand clock
Explanation: A sand clock, or hourglass, measures time intervals based on the flow of sand or granular material through a narrow opening between two chambers.
275. Which ancient civilization is credited with the invention of the sundial?
ⓐ. Egyptian
ⓑ. Roman
ⓒ. Greek
ⓓ. Chinese
Correct Answer: Egyptian
Explanation: The ancient Egyptians are credited with the invention of the sundial, using it to measure time by tracking the shadow cast by the sun.
276. Which ancient civilization is known for using water clocks as timekeeping devices?
ⓐ. Babylonian
ⓑ. Persian
ⓒ. Chinese
ⓓ. Indian
Correct Answer: Chinese
Explanation: The ancient Chinese are known for using water clocks, known as clepsydras, as timekeeping devices for various purposes including rituals, astronomy, and everyday life.
277. What type of error persists consistently in the same direction and affects the accuracy of measurements?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Systematic error
Explanation: Systematic error persists consistently in the same direction and affects the accuracy of measurements by introducing a bias in the results.
278. Which type of error occurs unpredictably and varies randomly in magnitude and direction?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Random error
Explanation: Random error occurs unpredictably and varies randomly in magnitude and direction, affecting the precision of measurements rather than their accuracy.
279. Which type of error can be reduced by taking multiple measurements and averaging the results?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Random error
Explanation: Random error can be reduced by taking multiple measurements and averaging the results, as random errors tend to cancel each other out over repeated trials.
280. Which type of error is caused by flaws or limitations in the measuring instruments themselves?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Instrumental error
Explanation: Instrumental error is caused by flaws or limitations in the measuring instruments themselves, leading to inaccuracies in the measurements obtained.
281. Which type of error is attributed to mistakes or inconsistencies in the way measurements are taken?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Human error
Explanation: Human error is attributed to mistakes or inconsistencies in the way measurements are taken, such as misreading instruments or improper technique.
282. Which type of error can be minimized by calibrating measuring instruments regularly?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Instrumental error
Explanation: Instrumental error can be minimized by calibrating measuring instruments regularly to ensure they are accurate and reliable.
283. Which type of error can be identified and corrected through careful experimental design and control?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Systematic error
Explanation: Systematic error can be identified and corrected through careful experimental design and control, such as using calibration standards or adjusting experimental procedures.
284. Which type of error affects the reproducibility and consistency of measurements over repeated trials?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Random error
Explanation: Random error affects the reproducibility and consistency of measurements over repeated trials by introducing variability in the results.
285. Which type of error is often reduced by improving the sensitivity and precision of measuring instruments?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Instrumental error
Explanation: Instrumental error is often reduced by improving the sensitivity and precision of measuring instruments, which helps to minimize inaccuracies in measurements.
286. Which type of error can lead to a consistent overestimation or underestimation of the true value being measured?
ⓐ. Systematic error
ⓑ. Random error
ⓒ. Instrumental error
ⓓ. Human error
Correct Answer: Systematic error
Explanation: Systematic error can lead to a consistent overestimation or underestimation of the true value being measured, affecting the accuracy of the results.
287. Which method involves taking multiple measurements of the same quantity and calculating the average to reduce random errors?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Averaging
Correct Answer: Averaging
Explanation: Averaging involves taking multiple measurements of the same quantity and calculating the average to reduce random errors and improve the precision of the measurement.
288. Which method involves adjusting measuring instruments to a known standard to minimize instrumental errors?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Verification
Correct Answer: Calibration
Explanation: Calibration involves adjusting measuring instruments to a known standard to minimize instrumental errors and ensure accurate measurements.
289. Which method involves using identical experimental conditions for different measurements to reduce systematic errors?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Verification
Correct Answer: Replication
Explanation: Replication involves using identical experimental conditions for different measurements to reduce systematic errors and enhance the reliability of the results.
290. Which method involves comparing measurements from different methods or instruments to verify accuracy and consistency?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Verification
Correct Answer: Verification
Explanation: Verification involves comparing measurements from different methods or instruments to verify accuracy and consistency, ensuring reliable measurement results.
291. Which method involves ensuring that the measuring instruments are adjusted to a consistent reference point?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Verification
Correct Answer: Standardization
Explanation: Standardization involves ensuring that the measuring instruments are adjusted to a consistent reference point or standard, facilitating accurate and uniform measurements.
292. Which method involves conducting careful experimental design to minimize errors from the outset?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Control
Correct Answer: Control
Explanation: Control involves conducting careful experimental design to minimize errors from the outset, including controlling variables and conditions during measurements.
293. Which method involves using statistical techniques to identify and reduce errors in experimental data?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Error analysis
Correct Answer: Error analysis
Explanation: Error analysis involves using statistical techniques to identify and reduce errors in experimental data, improving the accuracy and reliability of measurements.
294. Which method involves training personnel to minimize errors caused by inconsistent techniques or practices?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Training
Correct Answer: Training
Explanation: Training involves educating and training personnel to minimize errors caused by inconsistent techniques or practices, ensuring reliable measurement results.
295. Which method involves using quality control measures to monitor and improve the accuracy of measurements over time?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Quality assurance
Correct Answer: Quality assurance
Explanation: Quality assurance involves using quality control measures to monitor and improve the accuracy of measurements over time, maintaining consistent standards of measurement.
296. Which method involves documenting all steps and procedures in measurement to ensure transparency and reproducibility?
ⓐ. Calibration
ⓑ. Standardization
ⓒ. Replication
ⓓ. Documentation
Correct Answer: Documentation
Explanation: Documentation involves documenting all steps and procedures in measurement to ensure transparency and reproducibility of results, minimizing errors due to oversight or inconsistency.
297. What term describes the range within which the true value of a measurement is expected to lie?
ⓐ. Accuracy
ⓑ. Precision
ⓒ. Tolerance
ⓓ. Uncertainty
Correct Answer: Uncertainty
Explanation: Uncertainty in measurement refers to the range within which the true value of a measurement is expected to lie, taking into account errors and variations.
298. Which type of uncertainty arises from limitations in the measuring instruments and the methods used?
ⓐ. Systematic uncertainty
ⓑ. Random uncertainty
ⓒ. Instrumental uncertainty
ⓓ. Human uncertainty
Correct Answer: Instrumental uncertainty
Explanation: Instrumental uncertainty arises from limitations in the measuring instruments and the methods used, affecting the accuracy and reliability of measurements.
299. Which type of uncertainty can be reduced by improving the precision and sensitivity of measuring instruments?
ⓐ. Systematic uncertainty
ⓑ. Random uncertainty
ⓒ. Instrumental uncertainty
ⓓ. Human uncertainty
Correct Answer: Random uncertainty
Explanation: Random uncertainty can be reduced by improving the precision and sensitivity of measuring instruments, which helps to minimize variations in measurements.
300. Which type of uncertainty results from consistent errors in the measurement process that affect all measurements in the same way?
ⓐ. Systematic uncertainty
ⓑ. Random uncertainty
ⓒ. Instrumental uncertainty
ⓓ. Human uncertainty
Correct Answer: Systematic uncertainty
Explanation: Systematic uncertainty results from consistent errors in the measurement process that affect all measurements in the same way, leading to inaccuracies in the results.
The topic Units and Measurements is fundamental to Physics because it defines how physical quantities are expressed and compared. According to the NCERT/CBSE syllabus, this chapter discusses measurement of length, mass, time, accuracy, precision, systematic and random errors, significant figures, and dimensional formulae. These topics are extremely important for board exams and also serve as a foundation for solving advanced problems in competitive exams like JEE, NEET, and state-level tests. To help with exam preparation, we provide 398 MCQs with step-by-step explanations divided into 4 practice-friendly parts. In this third part, you will find another 100 multiple-choice questions focusing on dimensional analysis and error-based problem solving.
- 👉 Total MCQs in this chapter: 398.
- 👉 This page contains: Third set of 100 solved MCQs with detailed explanations.
- 👉 Includes dimensional analysis and error-related numerical problems.
- 👉 Very helpful for JEE/NEET aspirants and board exam students.
- 👉 Use the navigation buttons above the MCQs to continue or explore other chapters.