Physics · Science General
Units and Measurement
1,044 Questions
Master the fundamentals of physics with these practice questions on units and measurement. The topics include fundamental SI units, derived quantities, and specific units for power, force, and light. These questions are essential for building a strong foundation for competitive exams.
SI fundamental unitsUnits of powerDerived quantities unitsThermal energy unitsVolume measurement unitsElectric current units
Units and Measurement Questions
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Second (s)
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Metre (m)
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Ampere (A)
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Candela (cd)
A
Correct answer
Explanation
The SI unit of time is the second (s). Metre is for length, ampere for electric current, and candela for luminous intensity. The second is defined based on the radiation frequency of the cesium-133 atom.
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Milligrams
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Magnesium
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Manganese
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MegaWatts
B
Correct answer
Explanation
Mg is the chemical symbol for Magnesium, a metallic element with atomic number 12. It is an alkaline earth metal in Group 2 of the periodic table. Manganese is Mn, milligrams is a unit abbreviation (mg in lowercase), and MW stands for megawatts for power.
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weber
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weber / (meter square)
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Tesla / meter
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gauss
B
Correct answer
Explanation
The SI unit of magnetic flux density is Tesla, which equals weber per square meter (Wb/m²). Magnetic flux density (B field) measures magnetic field strength per unit area. Weber alone measures magnetic flux, not flux density. Gauss is a non-SI unit for magnetic flux density (1 Tesla = 10,000 gauss).
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Tesla
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Weber / (meter square)
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Weber
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Gauss/ (meter square)
C
Correct answer
Explanation
The SI unit of magnetic flux is Weber (Wb). Magnetic flux (Φ) is the total magnetic field passing through an area. Tesla is the unit of magnetic flux density (B field), not flux. Weber per square meter would be magnetic flux density, not flux. Gauss is a non-SI unit for magnetic flux density.
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length
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speed
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time
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none of these
A
Correct answer
Explanation
A light year is the distance light travels in one vacuum year (about 9.46 trillion kilometers). Despite containing the word 'year', it measures astronomical distance (length), not time or speed.
C
Correct answer
Explanation
Ohms is correctly identified as the unit of electrical resistance, named after Georg Ohm who formulated Ohm's Law (V=IR). Newton measures force, Mhos (now called Siemens) measures conductance (the inverse of resistance), and Cadila is not a physical unit. Resistance is fundamental to electrical circuits and determines how much a material opposes current flow.
D
Correct answer
Explanation
The Ampere (A) is the standard International System of Units (SI) unit for electric current. Ohm is the unit for resistance, Farad for capacitance, and Mho (an older term for Siemens) for conductance.
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Ammeter
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Cubit
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Parsec
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Angstrom
A
Correct answer
Explanation
An ammeter is an instrument used to measure electric current in amperes. A cubit, parsec, and angstrom are all units used to measure length or distance at various scales (human, astronomical, and atomic).
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One Kilowatt power consumed in 1 Hr
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One Watt power consumed in 1 Hr
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One Megawatt power consumed in 1 Hr
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One Amperes of current consumed in one second
A
Correct answer
Explanation
One unit of electricity is defined as one kilowatt-hour (kWh), which means using 1 kilowatt (1000 watts) of power for 1 hour. This is the standard unit for billing residential electricity consumption worldwide.
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a.Temperature
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b.Pressure
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c.Energy
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d.Heat
C
Correct answer
Explanation
Joule is the SI unit of energy or work. It measures the amount of energy transferred when a force of one newton acts over a distance of one meter.
C
Correct answer
Explanation
Paper is measured in reams (typically 500 sheets) and caliper (thickness measurement). This standard industry practice allows for consistent paper quantity and thickness specifications in printing and manufacturing.
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Temperature pressure
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Energy
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Heat
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None of these
D
Correct answer
Explanation
One joule equals 10^7 ergs because 1 J = 1 kg·m^2/s^2 and 1 erg = 1 g·cm^2/s^2, so 1 J = (1000 g) × (100 cm)^2/s^2 = 10^7 erg.
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Ohm
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Watt
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Ampere
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None of these
C
Correct answer
Explanation
The ampere is the SI base unit for electric current, measuring the flow of electric charge. Ohm is the unit of electrical resistance, and watt is the unit of power.
D
Correct answer
Explanation
The joule is the unit of energy in the MKS (meter-kilogram-second) system, which is the basis of the modern SI system. The erg is the energy unit in the CGS system, while volt measures potential difference and ohm measures resistance.