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easyQ. No. 12091-what-is-the-si-unit-of-amount-of-substance

What is the SI unit of amount of substance?

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Learners should write the given quantity, convert all values to compatible units, apply the defining relation and attach the correct final unit. The correct option must match the quantity, standard unit and physical meaning together. Option A (“Second”) is incorrect because it represents a different unit, dimension, instrument, quantity or measurement relationship from the one asked. Option B (“Candela”) is incorrect because it represents a different unit, dimension, instrument, quantity or measurement relationship from the one asked. Option C (“Lux”) is incorrect because it represents a different unit, dimension, instrument, quantity or measurement relationship from the one asked. The answer is selected because its unit and physical meaning match the question exactly.

ASecond
BCandela
CLux
DMole
Correct Answer: MoleYour Answer: D

Explanation

e is the SI base unit of amount of substance. Option A (“Second”) is incorrect because it represents a different unit, dimension, instrument, quantity or measurement relationship from the one asked. Option B (“Candela”) is incorrect because it represents a different unit, dimension, instrument, quantity or measurement relationship from the one asked. Option C (“Lux”) is incorrect because it represents a different unit, dimension, instrument, quantity or measurement relationship from the one asked. Match the quantity with its definition, SI unit and dimension. This keeps the selected index, answer and explanation consistent.e is the SI base unit of amount of substance. Option A, “Second”, is incorrect for this question because it does not match the precise location, process, landform, climatic feature or geographical relationship identified by the evidence. Option B, “Candela”, is incorrect for this question because it does not match the precise location, process, landform, climatic feature or geographical relationship identified by the evidence. Option C, “Lux”, is incorrect for this question because it does not match the precise location, process, landform, climatic feature or geographical relationship identified by the evidence. Mole is the SI base unit of amount of substance.

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Units and Measurements FAQs

Common questions and clear answers for this topic.

What are Units and Measurements and which system is internationally accepted?

Units and Measurements involve quantifying physical quantities. The SI (Systeme International) is the internationally accepted system with 7 base units: metre (m) for length, kilogram (kg) for mass, second (s) for time, ampere (A) for electric current, kelvin (K) for temperature, mole (mol) for amount of substance, and candela (cd) for luminous intensity. Units and Measurements is an important Physics topic for SSC CGL, Railway, and UPSC.

What are the units of important physical quantities?

Important Physical Quantities and SI Units: Force - Newton (N), Pressure - Pascal (Pa), Energy/Work - Joule (J), Power - Watt (W), Electric charge - Coulomb (C), Electric potential - Volt (V), Resistance - Ohm, Capacitance - Farad (F), Frequency - Hertz (Hz), Temperature - Kelvin (K) or Celsius (C). These units are frequently asked in SSC CGL, Railway NTPC, and Physics GK sections.

What are the common unit conversions needed for competitive exams?

Important Unit Conversions: Length: 1 km = 1000 m, 1 m = 100 cm, 1 inch = 2.54 cm, 1 foot = 12 inches. Mass: 1 kg = 1000 g, 1 quintal = 100 kg, 1 metric ton = 1000 kg. Area: 1 hectare = 10,000 sq m, 1 acre = 4047 sq m. Speed: 1 km/hr = 5/18 m/s. Pressure: 1 atm = 101325 Pa = 760 mmHg. Temperature: C = (F-32) x 5/9, K = C + 273.15.

What is the difference between scalar and vector quantities?

Scalar quantities have only magnitude (no direction): mass, length, time, speed, temperature, energy, volume, density. Vector quantities have both magnitude and direction: displacement, velocity, acceleration, force, momentum, electric field. Speed (scalar) vs Velocity (vector): Speed is distance/time, Velocity is displacement/time. These distinctions are important for Physics questions in SSC CGL, NDA, and Railway exams.

What are the important measuring instruments and what they measure?

Important Measuring Instruments: Thermometer (temperature), Barometer (atmospheric pressure), Hygrometer (humidity), Lactometer (purity of milk), Seismograph (earthquakes), Speedometer (speed of vehicle), Altimeter (altitude), Ammeter (electric current), Voltmeter (voltage), Galvanometer (small current), Manometer (gas pressure), Anemometer (wind speed), Hydrometer (specific gravity of liquids).