Maria

• UNIT NAME


  • PHYSICAL QUANTITIES AND MEASUREMENT
  • ENERGY SOURCES AND TRANSFER OF ENERGY
  • THERMAL PROPERTIES OF MATTER
  • PROPERTIES OF MATTER
  • FORCES AND MATTER
  • TURNING EFFECT OF FORCES
  • GRAVITATION
  • DYNAMICS
  • KINEMATICS
• The century we have stepped in, is the century of Physics. The modern disciplines Physics are strongly influencing not only all the branches of science but each and every aspect human life.
• To keep the students. abreast with the recent knowledge, it is a must that the curricula, at all the levels, be updated regularly by introducing the rapid and multidirectional development taking place in all the branches of Physics.
• Stephen Hawking: 'No one undertakes research in physics with the intention of winning a prize. It is the joy of discovering something no one knew before.'
• Physics Derived from Ancient Greek 'physicos' meaning 'knowledge of nature'.
• Main branches of Physics

  • Mechanics
  • Thermodynamics
  • Electricity
  • Magnetism
  • Atomic Physics
  • Optics
  • Sound
  • Nuclear physics
  • Particle physics
  • Astrophysics
  • Plasma physics
  • Geo physics
• Society's reliance on technology represents the importance of physics in daily life. Many aspects of modern society would not have been possible without the important scientific discoveries made in the past. These discoveries became the foundation on which current technologies were developed.
• Discoveries such as magnetism, electricity, conductors and others made modern conveniences, such as television, computers, smart phones, medical instruments, other business and home technologies possible. Moreover, modern means of transportation, such as aircraft and telecommunications, have drawn people across the world closer together all rely on concepts of physics.
• Physical quantity


  A physical property of a phenomenon, body, or substance that can be quantified by measurement
• Fundamental physical quantities


  • Length
  • Mass
  • Time
  • Electric current
  • Temperature
  • Amount of substance
  • Luminous intensity
• Derived physical quantities


  • Volume
  • Velocity
  • Force
  • Density
  • Acceleration
• Some Physical quantities are unit-less. Such as Elastic modulus, Plane angle and solid angle
• The notion of physical dimension of a physical quantity was introduced by Joseph Fourier in 1822 by convention, physical quantities are organized in a dimensional system built up upon base quantities, each of which is regarded as having its own dimension.
• The length is defined as the minimum distance between two points lying on same object.
• Fundamental quantities and their S.I units

  • Length (meter, m)
  • Mass (kilogram, kg)
  • Time (second, s)
  • Electric current (Ampere, A)
  • Temperature (Kelvin, K)
  • Amount of substance (mole, mol)
  • Luminous intensity (candela, cd)
• Derived quantities and their S.I units

  • Volume (cubic meter, m3)
  • Velocity (meter per second, m/s)
  • Force (Newton, N)
  • Density (kilogram per cubic meter, kg/m3)
  • Acceleration (meter per second square, m/s2)
• Some physical quantities are unitless, such as Elastic modulus, Plane angle and solid angle
• The notion of physical dimension of a physical quantity was introduced by Joseph Fourier in 1822
• Length


  The minimum distance between two points lying on the same plane
• Instruments used to measure physical quantities

  • Air gauges
  • Hydrometer
• Measuring physical quantities correctly with instruments is not an easy task for scientists and engineers
• Scientists are seriously concerned with the accuracy of the instrument and its synchronization
• Many of the instruments we use today are inventions of pioneers of science
• The basic physical quantities that we use in our daily life are measured with basic and simple instruments
• Meter (m)


  The SI unit of length, defined as the length of the path traveled by light in vacuum during the time interval of 1/299 792 458 of a second
• Meter rule


  • A device used to measure length of different objects
  • 1m = 100 cm
  • Each cm is divided into 10 mm
• Vernier caliper


  • A precision instrument used to measure internal and external distances accurately
  • Has both imperial and metric scales
  • Has main jaws for external diameter and smaller jaws for internal diameter
  • Some models have a depth gauge
• Reading a Vernier caliper

  1. Place the object between the jaws

  2. Note the main scale reading

  3. Count the next line of Vernier scale after zero coinciding main scale

  4. Add the two readings for total
• Micrometer screw gauge


  • Used for measuring extremely small dimensions
  • Works on the principle of converting small distances into larger ones by measuring the rotation of the screw
• Reading a micrometer screw gauge

  1. Turn the thimble until the anvil and spindle gently grip the object

  2. Take the main scale reading at the edge of the thimble

  3. Take the thimble scale reading opposite the datum line of the main scale, multiply by least count

  4. Add main scale and thimble readings
• Kilogram (kg)


  The SI unit of mass, equal to the mass of the international prototype of the kilogram, a platinum-iridium standard kept at the International Bureau of Weights and Measures
• Physical balance


  • An instrument used for measurement of mass in a laboratory
  • Works on the principle of moments
  • Consists of a light and rigid beam, a metallic pillar, a wooden base, two pans, a metallic pointer and an ivory scale
  • The plumb line indicates whether the balance is horizontal
• Electronic balance


  • An electronic instrument that works on the principle of balancing forces
  • Available in different measurement ranges such as microgram, milligram and kilogram
• Second (s)


  The SI unit of time, defined as 9 192 631 770 times the period of vibration of radiation from the cesium-133 atom
• Stopwatch


  • Used to measure the time interval between two events
  • Mechanical stopwatch can measure up to 0.1 second
  • Digital stopwatch can measure up to 0.01 second
• Human reaction time causes random error in manual operation of stopwatches, typically 0.3-0.5 seconds
• Light gates can be used for more accurate time interval measurement
• Time unit conversions


  • 1 hour = 60 minutes
  • 1 hour = 3600 seconds
  • 1 minute = 60 seconds
  • 1 second = 1000 milliseconds
  • 1 second = 1000000 microseconds
• Prefixes


  • Specifiers that indicate multiples or fractions of units
  • Commonly used to express units of physical quantities that are very big or very small
• Only a narrow set of prefixes have been recognized by standards organizations