Content text CLASS 11 PHYSICS CHAPTER-1 UNITS AND MEASUREMENT.pdf
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INTRODUCTION TO MEASUREMENT UNITS AND MEASUREMENTS Class 11th Physics INTRODUCTION TO MEASUREMENT To measure a physical quantity like length, mass and time, we require a standard of measurement. This standard of measurement is called the unit of that physical quantity. For example, the unit of length is metre, and a standard length of 1 metre has a precise definition. To measure the length of an object, we need to determine how many times this standard-length metre is contained in the length of the object. The comparison of a physical quantity with a standard quantity is called measurement. Units of Measurement The units of measurement are the collection of standard and other units that are used to measure various physical quantities. We have been using different units to measure these quantities like length, mass, volume, current, temperature, etc. Basic Units of Measurement Entity Base Unit Name Abbreviation Mass Kilogram Kg Length Meter M Time Second S Amount of matter Mole Mol Electric current Ampere A Luminosity Candela Cd Temperature Kelvin k Metric Units of Measurement The metric units of measurement in mathematics are standard units defined to measure length, height, weight, area, and capacity (volume). Quantity Units of Measurement Length Meter, Kilometer, Centimeter, Millimeter, Feet, Yard, Inch, Mile Mass Gram, Milligram, Kilogram, Ounce, Pound, Ton Volume Litre, Millilitre, Kilolitre, Gallon, Pint, Fluid Ounce Time Second, Minute, Hour, Day, Month, Week, Year Temperature Kelvin, Celsius, Fahrenheit, CHAPTER-1
INTRODUCTION TO MEASUREMENT UNITS AND MEASUREMENTS Class 11th Physics Imperial Units of Measurement Imperial units of measurement are the units from the British Imperial System (System of Weights and Measures used in Great Britain). the imperial system uses different units to measure the physical quantities like length, mass, volume, and area. Physical Quantity Imperial Units Length foot, inch, yard, mile Mass ounce, pound, stone, ton Capacity gallon, pint, quart, fluid ounce Units of Measurement for Length System Units of Measurement Conversion Metric Units Centimeter (cm) 1 cm = 10mm Meter (m) 1 m = 100cm Kilometer (km) 1 km = 1000m Millimeter (mm) 1 mm = 0.001m Imperial Units Foot (feet) 1 foot = 12 inch Inches (inch) 1 inch = 0.83333 feet Mile 1 mile = 5280 feet Yard 1 yard = 3 feet = 36 inch Units of Measurement for Mass System Units of Measurement Conversion Metric Units Milligram (mg) 1 mg = 0.001g Gram (g) 1 g = 1000mg Kilogram (kg) 1 kg = 1000g Imperial Units Ounce (oz) 1 oz = 0.0625lb Pound (lb) 1lb = 16oz Ton 1 ton = 2000lbs Units of Measurement for Volume System Units of Measurement Conversion Metric Units Millilitre (ml) 1 m = 0.001 l Litre (l) 1 l = 1000 ml Kilolitre (kl) 1 kl = 1000 l Cubic Centimeter (cm3 ) 1 l = 1000 cm3 Imperial Units Fluid ounce (fl. oz.) 1 fl. oz. = 1/20 pt
INTRODUCTION TO MEASUREMENT UNITS AND MEASUREMENTS Class 11th Physics Gallon (gal) 1gal = 128 fl. oz. Pint (pt) 1 pt = 16 fl. oz. Units of Measurement for Temperature Units of Measurement Conversion Celsius (C) 0°C = 273.15K = 32°F Kelvin (K) 0 K = -273. 15°C = -459.57°F Fahrenheit (F) 0°F = -17.778°C = 255.372K Units of Measurement of Time Units of Measurement Conversion Second (s) 1 s = 1/60 min Minute (min) 1 min = 60 s Hour (hr) 1 hr = 60 min = 3600 s Day 1 day = 24 hr Week 1 week = 7 days Month 1 month = 4 weeks Year 1 year = 12 months System of Units There are seven base units in it and 22 units are derived out of the same. These units can be expressed either as fractional quantities or as standard multiples and are expressed through multipliers with powers of 10 ranging from 10-24 to 1024. A unit can be defined as a physical well quantity that is well defined and against which quantities are compared during measurement. A complete set of fundamental and derived units is called a system of units. There are different systems of units, among which MKS, CGS, and FPS were used extensively. System of Units Physical Quantities Unit CGS System Length Centimetre (cm) Mass Grams (g) Time Seconds (s) MKS System Length Metre (m) Mass Kilograms (kg) Time Seconds (s)