Physics Class: Reflection and Refraction

Reflection of Light

• When light bounces back from a surface, it is called reflection.
• The angle of incidence is equal to the angle of reflection.
• There are two types of reflection: specular and diffuse.

Refractive Index

• The refractive index of a medium is a measure of how much light bends as it passes through the medium.
• It is the ratio of the speed of light in a vacuum to the speed of light in the medium.
• A higher refractive index indicates a greater bending of light.

Refraction of Light

• When light travels from one medium to another, it changes direction.
• This bending of light is called refraction.
• Refraction occurs because the speed of light changes as it passes from one medium to another.

Critical Angle

• The critical angle is the angle of incidence at which the angle of refraction is 90 degrees.
• When the angle of incidence is greater than the critical angle, total internal reflection occurs.
• This phenomenon is used in optical fibers to transmit light over long distances.

Beer-Lambert Law

• This law describes the relationship between the absorbance of a solution and the concentration of the analyte.
• It states that the absorbance of a solution is directly proportional to the concentration of the analyte and the path length of the light beam through the solution.
• Used in analytical chemistry to determine the concentration of substances.

Dispersive Power

• The dispersive power of a material is a measure of its ability to separate different wavelengths of light.
• It is defined as the difference between the refractive indices of the material at two specific wavelengths, divided by the refractive index at a reference wavelength.
• Used in the design of prisms and lenses.

Interference of Light

• The phenomenon of interference occurs when two or more waves of light interact with each other.
• When the waves are in phase, they interfere constructively, resulting in an increase in amplitude.
• When the waves are out of phase, they interfere destructively, resulting in a decrease in amplitude.

Absolute Zero of Temperature

• The absolute zero of temperature is theoretical temperature at which all molecular motion stops.
• It is equal to -273.15 degrees Celsius or 0 Kelvin.
• It is impossible to reach absolute zero in practice.

Charles Law

• States that the volume of an ideal gas is proportional to its absolute temperature, if the pressure is kept constant.
• It can be expressed as V/T = constant.
• It is one of the gas laws that describe the behavior of ideal gases.

Boyle's Law

• It states that the pressure of an ideal gas is inversely proportional to its volume, if the temperature is kept constant.
• Can be expressed as P*V = constant.
• Used to predict the behavior of gases under changing pressure and volume conditions.

Isobaric Process

• A thermodynamic process where the pressure remains constant.
• The volume and temperature may change.
• For example, heating a gas in a container with a piston that can move freely.

Isochoric Process

• A thermodynamic process where the volume remains constant.
• The pressure and temperature may change.
• For example, heating a gas in a sealed container.

Isentropic Process

• A thermodynamic process where the entropy remains constant.
• It often involves adiabatic processes, where there's no heat exchange with the surroundings.
• In this process, the energy change is purely due to work done.

Coefficient of Thermal Conductivity

• Measured as the rate of heat transfer through a material per unit area and per unit temperature gradient.
• A material with a high coefficient of thermal conductivity will transfer heat quickly.
• Used in the design of thermal insulation materials.

Isothermal Process

• A thermodynamic process where the temperature remains constant.
• The pressure and volume may change.
• An example is the compression of a gas slowly enough to maintain a constant temperature.

Stimulated Emission of Radiation

• A process in which an excited atom or molecule emits a photon when stimulated by a photon of the same energy level.
• It is used in lasers to produce coherent light.
• It results in amplification of light.

Properties of Sound Waves

• Sound waves are mechanical waves that require a medium to travel.
• They are longitudinal waves, meaning that the particles of the medium vibrate parallel to the direction of wave propagation.
• Sound waves can be reflected, refracted, and diffracted.

Ultrasonography

• A medical imaging technique that uses high-frequency sound waves to create images of internal organs and tissues.
• The sound waves are emitted from a transducer and reflected back from various tissues in the body.
• This technique is used for diagnosing a variety of conditions, including pregnancy, heart disease, and kidney stones.

Convex Lens

• It is a converging lens that causes parallel rays of light to converge at a point called the focal point.
• It can be used to magnify images, as found in magnifying glasses and microscopes.
• It is thicker at the center than at the edges.

Refraction of Light and Laws of Refraction

• The bending of light when it passes from one medium to another is called refraction.
• The first law states that the incident ray, refracted ray, and the normal at the point of incidence all lie in the same plane.
• The second law, Snell's Law, states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for a given pair of media.

Types of Thermometers

• Mercury thermometers utilize the expansion of mercury with increasing temperature.
• Alcohol thermometers use the expansion of alcohol.
• Digital thermometers use sensors to measure temperature electronically.

Wave

• A disturbance that travels through a medium or space, transferring energy but not necessarily matter.
• There are two primary types: transverse waves and longitudinal waves.

Mechanical Wave

• A wave that requires a medium to travel.
• Sound waves are an example, as they need air or another medium to propagate.

Angular Dispersion

• The separation of different wavelengths of light as they are refracted through a prism or grating.
• This is what produces the rainbow effect in a prism.

Spectrophotometer

• An instrument that measures the amount of light absorbed or transmitted by a sample at specific wavelengths.
• It is often used in science to analyze the composition or concentration of substances.

Stimulated Emission

• When an excited atom is stimulated to emit a photon by an incoming photon of the same energy.
• This is the principle behind lasers.

Interference of Light

• When two or more waves of light interact with each other, resulting in either constructive or destructive interference patterns.
• It depends on the phase difference between the waves.

Thermometer

• A device used to measure temperature.
• It works by measuring the expansion or contraction of a material, such as mercury or alcohol, in response to temperature changes.

Ideal Gas Equation

• States the relationship between pressure, volume, temperature, and the number of moles of an ideal gas.
• It is expressed as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature.

Oscillation

• A repetitive back and forth motion around a central point or equilibrium position.
• Examples include a pendulum swinging or a spring bouncing.

Velocity

• The rate of change of displacement with time.
• It is a vector quantity, meaning it has both magnitude and direction.

Acceleration

• The rate of change of velocity with time.
• It is also a vector quantity.
• Positive acceleration means an increase in velocity, while negative acceleration signifies a decrease in velocity.

Work

• The product of force and displacement in the direction of force.
• It is a scalar quantity, meaning it only has magnitude and no direction.

Energy

• The ability to do work.
• It exists in various forms, such as kinetic energy (associated with motion) and potential energy (associated with position).

Pressure

• The force applied per unit area.
• It is a scalar quantity.

Frequency

• The number of oscillations or cycles of a wave that occur per unit time.
• It is measured in Hertz (Hz).

Cohesive Force

• The force of attraction between molecules of the same substance.
• It is responsible for phenomena like surface tension.

Floatation

• The ability of an object to stay afloat in a fluid.
• It depends on the density of the object and the density of the fluid.

Capacitance

• The ability of a system to store electric charge.
• It is measured in Farads (F).
• Capacitors are electrical components designed to store charge.

Angle of Contact

• The angle at which a liquid surface meets a solid surface.
• It is influenced by the adhesive forces between the liquid and the solid, and the cohesive forces within the liquid.

Archimedes' Principle

• States that the buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.
• This principle explains why objects float or sink.

Centripetal Force

• A force that is directed towards the center of a circular path, necessary for an object to move in a circular motion.
• It is always perpendicular to the object's velocity.

Elasticity and Behavior of Molecules

• The ability of a material to return to its original shape after being deformed.
• It is determined by the intermolecular forces between molecules.
• Stronger intermolecular forces lead to higher elasticity.

Three Types of Stress

• Tensile stress: Occurs when a force pulls or stretches a material.
• Compressive stress: Occurs when a force pushes or compresses a material.
• Shear stress: Occurs when a force acts parallel to the surface of a material, causing it to slide or deform.