Physics

• Physics is the branch of natural science that studies matter, its motion, behavior through space and time, and the related entities of energy and force
• Physics aims to understand how the universe behaves and is considered the mother of all sciences
• Physics can be defined as dealing with the behavior and structure of matter and the energy that drives matter
• The main branches of Physics include Mechanics, Thermodynamics, Electricity, Magnetism, Atomic Physics, and Optics
• Mechanics is concerned with the laws of motion and gravitation
• Thermodynamics deals with heat, temperature, and their relation to energy and work
• Electricity studies the properties of charges in rest and motion
• Magnetism focuses on the magnetic properties of materials
• Atomic Physics deals with the composition, structure, and properties of the atom
• Optics studies the physical aspects of light and its properties
• Physics is much concerned with matter and energy and the interaction between them, explained with the help of describing the mathematical relations between various physical quantities
• All physical quantities are important for describing the nature around us, and they can be quantified by measurement
• A physical quantity is a physical property of a phenomenon, body, or substance that can be quantified by measurement
• Physical quantities are classified into two categories: fundamental quantities and derived physical quantities
• Fundamental physical quantities are those that cannot be explained by other physical quantities, and there are seven fundamental physical quantities listed in table 1.1 along with their units
• Derived physical quantities are explained on the basis of fundamental physical quantities
• Physical quantities are either calculated mathematically or measured through an instrument
• The notion of physical dimension of a physical quantity was introduced by Joseph Fourier in 1822, and physical quantities are organized in a dimensional system built 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 the same plane
• The meter (m) is the SI unit of length and is defined as the length of the path traveled by light in vacuum during the time interval of 1/299 792 458 of a second
• A meter rule is a device used to measure the length of different objects, and it can measure up to 1mm as the smallest reading
• The Vernier Caliper is a precision instrument that can measure internal and external distances extremely accurately, with both imperial and metric scales
• The Micrometer Screw Gauge is used for measuring extremely small dimensions and works on the principle of converting small distances into larger ones by measuring the rotation of the screw
• The kilogram is the SI unit of mass and is equal to the mass of the international prototype of the kilogram, a platinum-iridium standard kept at the International Bureau of Weights and Measures
• Zero Error Check:

  • Observed reading: 2.0+0.25 = 2.25mm, no correction needed
  • Positive Zero Error: Reading = +0.07 mm, corrected reading = 2.32mm, actual reading = 2.25mm
  • Negative Zero Error: Reading = -0.02mm, corrected reading = 2.23mm, actual reading = 2.25mm
• The physical balance is an instrument used for the measurement of mass, working on the principle of moments, consisting of a light and rigid beam of brass, a metallic pillar, a wooden base, two pans, a metallic pointer, and an ivory scale
• The electronic balance is an electronic instrument configured with integrated circuits, working on the principle of balancing forces, available in different ranges of measurement such as microgram, milligram, and kilogram
• Scientific Notation:

  • Scientific notation is a simple method of writing very large or very small numbers as powers of ten, making calculations of such numbers easier
• Numbers in Scientific Notation are made up of three parts: The coefficient, the base (which must be 10), and the exponent (which can be negative or positive)
• In Scientific Notation, the coefficient must be equal to or greater than one, the base must be 10, and the exponent can be negative or positive
• To convert a mass of the Sun, 2 000 000 000 000 000 000 000 000 000 000 kg, into Scientific Notation:

  • Step 1: Move the decimal to the left, writing in terms of the base of ten
  • Step 2: The mass of the Sun in Scientific Notation is 2.00 x 10^30 kg
• To convert the mass of an electron, 9.11 x 10^-31 kg, into standard form:

  • Step 1: The decimal lies in the middle of the value
  • Step 2: Move the decimal 31 steps to the left, resulting in 0.000 000 000 000 000 000 000 000 000 911 kg
• The three common phases of matter are solid, liquid, and gas. A solid maintains a fixed shape and size, a liquid takes on the shape of its container, and a gas expands to fill its container
• Density is defined as mass of substance per unit volume, denoted by the Greek letter ρ. The SI unit for density is kg/m^3
• The density of a substance can be found either mathematically or experimentally by taking the density of water at 4°C as a reference, known as relative density or 'Specific gravity'
• Significant figures are the reliably known digits in a value
• To find the number of significant figures in the area of a cylinder with a diameter of 5 cm:

  • Step 1: Calculate the radius of the cylinder
  • Step 2: Calculate the area of the cylinder
  • Step 3: The area of the cylinder is 1.9 mm^2, therefore there are 2 significant figures
• Physics is the branch of science dealing with studies of matter, its composition, properties, and interaction with energy
• Physics branches are classified based on different areas of study with different approaches
• There are two types of physicists: theoretical and experimental physicists