Thermodynamics and Laws

• Physics encompasses the fundamental laws and principles governing the universe, covering a vast range of phenomena from subatomic particles to the cosmos
• Thermodynamics deals with heat, work, temperature, and energy, focusing on the laws that govern the behavior of energy at the macroscopic level

Thermodynamics

• The first law of thermodynamics states that energy is conserved; it can be transformed from one form to another, but cannot be created or destroyed
• The second law of thermodynamics introduces the concept of entropy, stating that the total entropy of an isolated system can only increase over time
• The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero
• Zeroth law of thermodynamics states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other

Mechanics

• Mechanics is the study of motion and forces, and is broadly divided into kinematics and dynamics
• Kinematics describes motion without considering the forces that cause it, focusing on displacement, velocity, and acceleration
• Dynamics relates motion to the forces that cause it, using Newton's laws of motion
• Newton's first law (law of inertia): An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by a force
• Newton's second law: The acceleration of an object is directly proportional to the net force acting on the object, is in the same direction as the net force, and is inversely proportional to the mass of the object (F=ma)
• Newton's third law: For every action, there is an equal and opposite reaction
• Work is defined as the force applied over a distance (W=Fd)
• Energy exists in various forms, including kinetic energy (energy of motion) and potential energy (energy of position or state)
• Power is the rate at which work is done or energy is transferred (P=W/t)

Electromagnetism

• Electromagnetism deals with the interaction between electric charges and magnetic fields
• Electric charge is a fundamental property of matter that can be positive or negative
• Coulomb's law describes the force between electric charges: like charges repel, and opposite charges attract
• Electric field is the force per unit charge exerted on a test charge
• Electric potential is the potential energy per unit charge at a given point in an electric field
• Current is the rate of flow of electric charge
• Resistance is the opposition to the flow of electric current
• Ohm's law relates voltage, current, and resistance (V=IR)
• Magnetism is caused by the motion of electric charges
• Magnetic field is the force field around a magnet or electric current
• Electromagnets are created by passing an electric current through a coil of wire
• Faraday's law of induction states that a changing magnetic field induces an electromotive force (voltage) in a circuit
• Maxwell's equations unify electricity and magnetism, describing how electric and magnetic fields are generated and interact

Optics

• Optics is the study of light and its behavior
• Reflection is the bouncing of light off a surface
• Refraction is the bending of light as it passes from one medium to another
• Lenses are used to focus or diverge light, forming images
• The human eye uses a lens to focus light onto the retina, allowing us to see
• Optical instruments such as telescopes and microscopes use lenses and mirrors to enhance our vision
• Wave optics describes light as a wave, explaining phenomena such as interference and diffraction
• Interference is the superposition of waves, which can result in constructive or destructive interference patterns
• Diffraction is the bending of waves as they pass through an opening or around an obstacle
• Polarization is the alignment of the electric field vector of light waves, which can be used to filter or manipulate light
• The electromagnetic spectrum includes radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays