💠Terminologies in Progressive Wave Motion💠

➖Amplitude
➖Period
➖Wavelength
➖Frequency
➖Wave velocity
➖Phase or phase angle (O)
➖Phase difference
➖Path difference
➖Time difference


🔹Amplitude (A): The amplitude of a wave is the maximum displacement of any particle of the medium from its equilibrium position.

🔹Period (T): Period (T) of a wave is the time taken by any particle of the medium to complete one vibration during a period (T).

🔹Wavelength (λ): Wavelength (λ) is equal to the distance between two consecutive particles of the medium which are in the same state of vibration it is equal to the distance travelled by the wave by its time period (T).

🔹Frequency (f): It is the number of vibrations made per second by any particles of the medium (f = 1/T). Since the frequency of a wave is a characteristic property of the source which is producing the wave motion, hence, the frequency of a wave does not change when a wave travels from one medium to another medium.

🔹Phase or Phase Angle (Φ): It represents the state of vibration of the particle of a medium with respect to its mean position.

🔹Phase Difference Δ(Φ): It represents the different state of vibration of a particle at two different instants (or) any pair of particles at the same instant. ΔΦ = Φ2 – Φ1.

Wave Velocity (v): It is the distance travelled by the wave in one second (v = λ/T). It is determined by the mechanical properties of the medium through which the wave propagates. The velocity of wave motion is measured with respect to the medium, the wave velocity changes when the medium is in motion i.e. speed of sound through air changes when the wind is blowing.

⇒ Check: Sound Waves

There are two velocities associated with a wave. One is the wave velocity and the other one is particle velocity (which is the speed with which the particle of the medium vibrate when the wave passes through the medium).

🔹Path Difference (Δx) or (x): It indicates the distance between two points measured along the direction of propagation of the wave through the medium.

🔹Time Difference (ΔT): It indicates the time taken by the wave to travel from one point to another through the medium.

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🔷Matter In Our Surroundings🔷

Everything found in this universe is made up of some materials, scientists have named them as “matter.” For example, the food we eat, the air we breathe, stones, clouds, stars, plants, animals, water, dust, everything is categorized as matter.

♦️Characteristics of Particles of Matter
➖Particles of matter are very small, normally, not visible from naked eye.
➖Particles of matter keep moving continuously, which is known as the “kinetic energy.”
➖Kinetic energy of particles directly depends on the temperature, as temperature increases, the speed of the movement also increases.
➖The particles of matter have attracting force; therefore, they attract each other.
➖The attracting force of the particles keeps the particles together; however, the strength of the attracting force varies from one kind of matter to another.

States of Matter
Matter has three following states −
➖Solid State
➖Liquid State
➖Gaseous State

🧿Solid State
➖All the solid materials have a definite shape, distinct boundaries, and fixed volumes.
➖Most of the solid materials have negligible compressibility.
➖All the solid materials have a natural tendency to maintain their shape when subjected to outside force.
➖The solid materials can be broken under applied force, but it is very difficult to change their shape, as they are rigid.

🧿Liquid State
➖Unlike solids, liquids have no fixed shape; however, they have a fixed volume
➖Liquids take up the shape of the container in which they are kept.
➖Liquids have the property to flow and change shape.

🧿Gaseous State
➖Matter in the form of air, which is neither solid nor liquid, is known as gas. For example, oxygen, nitrogen, hydrogen, etc.
➖Unlike solid, gas has not definite size and shape.
➖The gases, such as liquefied petroleum gas (LPG – used in cooking); compressed natural gas (CNG – used as fuel in vehicles), etc. have high compressibility; therefore, large volume of a gas can be compressed into a small cylinder and can be transported easily.
➖Gases, normally, show the property of diffusing very fast into other gases. This is the reason that we can smell (either good or bad) from the distance.

🔷Matter Can Change its State
➖Water can exist in all three states, e.g. Ice as solid; water (H2O) as liquid; and water vapor as gas.
➖The temperature, at which solid melt and transform into the liquid (at the given atmospheric pressure), is known as “melting point.”
➖The melting point of a solid is an indication of the strength of the force of attraction between its particles.
➖The melting point of ice is 273.16 K, i.e. 00 C.
➖The process of melting (i.e. change of solid state into liquid state) is known as fusion.
➖The amount of heat energy, which is required to change 1 kg of a solid materials into liquid materials at a given atmospheric pressure, is known as the latent heat of fusion.
➖The temperature at which a liquid starts boiling at the given atmospheric pressure is known as “boiling point.”
➖The boiling point of water is 373 K i.e. 1000C.
➖A change of state of a matter directly from solid to gas without changing into liquid state (or vice versa) is known as “sublimation.”
➖The phenomenon i.e. change of a liquid into vapors at any temperature below its boiling point is known as “evaporation.”
➖Solid carbon dioxide (CO2) is stored under high pressure.
➖Solid CO2 gets converted directly into gaseous state once the pressure decreases to 1 atmosphere.
➖Atmosphere (atm) is a unit of measuring pressure exerted by the gas and the unit of pressure is Pascal (Pa); 1 atmosphere = 1.01 × 105 Pa.


🔷The Fourth State of Matter
➖Plasma is the state that consists of super energetic and super excited particles.
➖The super excited particles are found in the form of ionized gases. E.g. the fluorescent tube (which contains helium gas) and neon sign bulbs (which contain neon gas) consist of plasma.

Group 13 Elements (Boron Group):
Includes boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).
Boron is a metalloid with unique properties and forms covalent compounds.
Aluminum is widely used in industries due to its lightweight and corrosion-resistant nature.
Gallium is a metal with a low melting point, used in semiconductors and LED technology.

Group 14 Elements (Carbon Group):
Includes carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb).
Carbon is the basis of organic chemistry and has diverse allotropes, including diamond and graphite.
Silicon is a significant component of semiconductors and plays a vital role in modern electronics.

Group 15 Elements (Nitrogen Group):
Includes nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi).
Nitrogen is essential for life and exists as diatomic molecules in the atmosphere.
Phosphorus is crucial for biological processes and is used in fertilizers and detergents.

Group 16 Elements (Oxygen Group/Chalcogens):
Includes oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po).
Oxygen is vital for respiration and combustion processes.
Sulfur is widely used in the chemical industry and exists as elemental sulfur and various sulfide compounds.

Group 17 Elements (Halogens):
Includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
Halogens are highly reactive nonmetals and exist as diatomic molecules in their elemental form.
Chlorine is widely used as a disinfectant, and iodine is used in antiseptics.

Group 18 Elements (Noble Gases):
Includes helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
Noble gases have full valence electron shells, making them stable and unreactive.
Helium is used in balloons and as a coolant in various applications.

Group 16, 17, and 18 Compounds:
Students should know the preparation, properties, and uses of common compounds like sulfuric acid, hydrochloric acid, ozone, hydrogen peroxide, and ammonia.

General Trends in p-Block Elements:
Understanding periodic trends like atomic size, ionization energy, electronegativity, and electron affinity within the p-block elements.

Important Compounds:
Learn about important compounds like borax, boron trifluoride, silicones, phosphine, hydrogen halides, carbon dioxide, sulfur dioxide, etc.

Allotropes and Applications:
Understanding the various allotropes of carbon (diamond, graphite, fullerene) and their applications in technology.

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