Absorption spectrum is the range of frequencies of electromagnetic radiation readily absorbed by a substance by virtue of its chemical composition.

Acceleration is the rate of change of velocity.

The activity of a radioactive sample is the number of decays per unit time.

Air drag is a resistive force that acts on objects moving through air.

Alpha decay occurs when an unstable nucleus emits an alpha particle, which is essentially a helium nucleus made up of two protons and two neutrons ($^4_2 \text{He}$).

Alternators are devices that convert mechanical energy into electrical energy using the principles of electromagnetic induction.

Angular acceleration is the rate of change of angular velocity.

Angular displacement is the angle through which an object moves on a circular path. It is measured in radians.

Angular impulse is a concept in rotational motion that describes the change in angular momentum of a rigid body due to the application of torque over a period of time.

Angular momentum is the rotational equivalent of linear momentum. More precisely, it is the product of its moment of inertia and its angular velocity.

Angular velocity ($\omega$) is the rate of change of angular displacement. It is measured in radians per second (rad/s).

Antinodes are points on a standing wave where the displacement reaches its maximum value.

Atmospheric drag is the resistance experienced by an object moving through a planet’s atmosphere.

Average speed is the total distance traveled divided by the total time taken. It’s a scalar quantity.

Average velocity is the total displacement divided by the total time taken. It’s a vector quantity.

In beta minus decay, a neutron in the nucleus is converted into a proton, emitting an electron ($\beta^-$) and an antineutrino ($\bar{\nu}$):

$$
n \rightarrow p + e^- + \bar{\nu}
$$

In beta plus decay, a proton is converted into a neutron, emitting a positron ($\beta^+$) and a neutrino($\nu$):

$$
p \rightarrow n + e^+ + \nu
$$

Binding energy is the energy required to hold the nucleus together.

A black body is an idealized object that absorbs all radiation falling on it and emits radiation based on its temperature.

The Carnot cycle represents an idealized model of a heat engine that achieves the maximum possible efficiency for given reservoir temperatures.

The Carnot efficiency represents the maximum possible efficiency of a heat engine operating between two temperatures, $T_h$ (hot reservoir) and $T_c$ (cold reservoir).

Centripetal force is a force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.

Collisions are interactions where two or more objects exert forces on each other for a short time.

A compression is a region in a longitudinal wave where the particles of the medium are close together, resulting in a high-pressure area. In sound waves, compressions correspond to regions of increased air density and pressure.

Conduction is the transfer of thermal energy through a material without the movement of the material itself.

Angular momentum is conserved unless an external torque acts on the system.

In an isolated system, the total mechanical energy is conserved:

$$E_{\text{total}} = E_k + E_p = \text{constant}$$

Contact forces are forces that arise due to direct physical interaction between two objects.

Convection is the transfer of thermal energy through the movement of fluid particles, driven by differences in density.

A crest is the highest point of a wave, where the displacement of the medium is at its maximum positive value relative to the equilibrium position. In a transverse wave, crests correspond to peaks in the wave motion.

Critical damping occurs when a system returns to its equilibrium position in the shortest possible time without oscillating.

The decay constant, $\lambda$, measures how quickly a radioactive substance decays. It is defined as the probability of decay per unit time for a single nucleus.

Density refers to how much mass is contained in a given volume of the medium.

Diffraction is the spreading of waves as they pass through an aperture or around an obstacle.

The distance of closest approach is the minimum distance an alpha particle can reach during a head-on collision with a nucleus. This distance is determined using energy conservation.

The Doppler effect is the change in the observed frequency of a wave when there is relative motion between the source and the observer

Drag force is a resistive force that acts opposite to the direction of an object’s motion through a fluid (such as air or water).

Eddy currents are loops of induced current that form in conductors exposed to a changing magnetic field.

The efficiency ($\eta$) of a heat engine measures how effectively it converts input energy into useful work.

Efficiency quantifies how effectively a system converts input energy into useful output energy.

In an elastic collision, both momentum and kinetic energy are conserved.

Elastic potential energy is the energy stored in an elastic object, such as a spring, when it is compressed or stretched.

Elasticity describes how easily a medium returns to its original shape after being disturbed.

Electric circuits are systems where electric charge flows through a closed loop.

Electric current is the rate at which electric charge flows through a conductor.

An electric field is a region of space where a charge experiences a force.

The electric field strength $E$ is defined as the force per unit charge experienced by a small positive test charge $q$.

Electric potential is the amount of work done per unit charge in bringing a small positive test charge from infinity to a point in an electric field.

Electric potential difference, or voltage, is the energy per unit charge required to move a charge between two points in an electric field.

Electric potential energy is the energy stored in a system of charged particles due to their positions relative to each other.

Electromagnetic waves are composed of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation.

The electromotive force (emf) is the work done per unit charge to move a charge completely around a circuit, including through the battery.

The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule transitioning from a high energy state to a lower energy state.

Emissivity ($e$) measures how efficiently a surface radiates energy compared to an ideal black body.

Energy density is defined as the amount of energy stored per unit volume or mass of a substance.

Entropy is a measure of the disorder or randomness in a system. It quantifies the number of possible ways a system can be arranged.

Equipotential surfaces are imaginary surfaces where the gravitational potential is the same at every point.

Escape velocity is the minimum speed an object must have to break free from a gravitational field without any additional energy input.

Faraday’s law states that a changing magnetic flux through a loop induces an emf (electromotive force) in the loop.

The first law of thermodynamics states that the total energy of an isolated system is constant.

Friction is a force that opposes the motion of an object.

Fringe spacing refers to the distance between adjacent bright or dark fringes in an interference pattern, typically observed in double-slit experiments or diffraction patterns.

Gamma decay occurs when an excited nucleus releases excess energy by emitting a gamma ray, a high-energy photon.

The gravitational field strength ($g$) at a point is defined as the force per unit mass experienced by a small test mass placed at that point.

A gravitational field is a region of space where a mass experiences a gravitational force.

Gravitational potential ($V_g$) is the work done per unit mass to bring a small test mass from infinity to a point in a gravitational field.

Gravitational potential energy is the energy stored due to the position of an object in a gravitational field.

Heavy damping is defined as a type of damping where the body attains its equilibrium gradually without any oscillation.

The ideal gas law is the equation of state of a hypothetical ideal gas which relates the pressure, volume, temperature, and amount of substance in a gas.

Impulse describes how a force applied over a period of time changes an object's momentum.

The impulse-momentum theorem states that the impulse on an object is equal to the change in its momentum

Induced fission occurs when a nucleus splits after absorbing a neutron.

In an inelastic collision, momentum is conserved, but kinetic energy is not.

Inertia is the tendency of an object to resist changes in its state of motion.

An inertial reference frame is one where Newton’s first law holds true: an object at rest stays at rest, and an object in motion continues in a straight line at constant speed unless acted upon by a force.

Instantaneous acceleration is the acceleration at a specific moment in time.

Internal energy is the sum of kinetic energy and potential energy of a substance and is the result of the motion of the particles which make up the substance.

Internal resistance is the resistance within the battery itself, caused by the materials and chemical reactions inside it.

Irreversible processes are real-world processes that cannot be undone without leaving a net change in the system or surroundings.

Kinetic energy is the energy an object possesses due to its motion.

Length contraction is the phenomenon where an object in motion appears shorter along the direction of motion to a stationary observer.

Lenz’s law states that the direction of the induced emf is such that it opposes the change in magnetic flux that produces it.

This principle ensures the conservation of energy.

Light damping is when the amplitude of each oscillation is fractionally less than the previous one

A light-dependent resistor (LDR) is a resistor whose resistance decreases as the intensity of light falling on it increases.

The Lorentz transformations relate the coordinates of an event in one inertial frame to those in another moving at a constant velocity relative to the first.

Luminosity measures the amount of radiated electromagnetic energy per unit time.

Magnetic flux $\Phi$ quantifies the amount of magnetic field passing through a given surface.

Mechanical energy is the sum of an object's kinetic energy and potential energy.

Mechanical waves are waves that require a medium (such as air, water, or a solid) to propagate.

A mole is defined as the amount of substance containing as many particles (atoms, molecules, etc.) as there are atoms in 12 grams of carbon-12.

Momentum is a measure of how difficult it is to stop a moving object. It depends on two factors: the object's mass and its velocity.

A natural frequency is a frequency at which the system naturally oscillates when not disturbed by external forces.

Newton’s first law of motion states:

An object at rest stays at rest, and an object in motion stays in motion at a constant velocity, unless acted upon by a net external force.

Newton's second law of motion states:

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Newton’s third law of motion states:

For every action, there is an equal and opposite reaction.

Nodes are points on a standing wave where the displacement is always zero.

A non-inertial reference frame is one that is accelerating.

Nuclear fusion is the process where two light atomic nuclei combine to form a heavier nucleus, releasing an extraordinary amount of energy.

Ohm’s Law states that the current through a conductor is directly proportional to the potential difference across it, provided the temperature remains constant.

Orbital speed is the speed an object must have to maintain a stable circular orbit around a larger mass.

The parallax angle $p$ is defined as half the total angular shift of the star.

In a parallel circuit, resistors are connected across the same two points, providing multiple paths for current.

Path difference is the difference in distance traveled by the waves from their sources to the point of overlap.

In a perfectly inelastic collision, the colliding objects stick together and move as one mass after the collision.

The period ($T$) is the time taken for one complete revolution.

The photoelectric effect refers to the emission of electrons from a metal surface when light or other electromagnetic radiation shines on it.

A photon is a tiny particle that comprises waves of electromagnetic radiation.

Potential energy is the energy stored in an object due to its position or configuration.

A potentiometer is a three-terminal resistor with a sliding contact that forms an adjustable voltage divider.

Power is the rate at which energy is transferred or converted.

The power dissipated in a circuit component is the rate at which energy is transferred.

Pressure is the force applied per unit area.

Projectile motion is the motion of an object thrown or projected into the air, subject to only the acceleration of gravity.

Proper length ($L_0$) is the length of an object measured in the frame where the object is at rest.

Proper time ($\Delta t_0$) is the time interval between two events measured in the frame where the events occur at the same location.

Radiation is the transfer of thermal energy through electromagnetic waves, without the need for a medium.

Radioactive decay is the process by which an unstable atomic nucleus loses energy by radiation.

A rarefaction is a region in a longitudinal wave where the particles of the medium are spread apart, resulting in a low-pressure area. In sound waves, rarefactions correspond to regions of decreased air density and pressure.

A ray is a line drawn perpendicular to a wavefront, indicating the direction of wave propagation.

A reference frame is a coordinate system that allows us to measure the position, velocity, and time of events.

Reflection occurs when a wave strikes a surface and bounces back into the original medium.

Refraction is the bending of a wave as it passes from one medium to another, caused by a change in the wave’s speed.

The refractive index ($n$) of a medium is a measure of how much the wave slows down in that medium compared to a vacuum.

Resistance is a measure of how much a material opposes the flow of electric current.

Resistivity is a fundamental property of a material that quantifies how strongly it resists the flow of electric current.

Resonance occurs when the frequency of incoming infrared radiation matches the natural frequency of a molecule’s vibrational or rotational modes.

Reversible processes are idealized processes that occur in such a way that the system and its surroundings can be returned to their original states without any net change.

A rigid body is an idealized object in which the relative positions of all particles remain fixed, regardless of external forces or torques.

Rotational equilibrium is defined as the state of movement where angular acceleration is zero: total torque is zero.

Rotational kinetic energy or angular kinetic energy is kinetic energy due to the rotation of an object and is part of its total kinetic energy.

Scalar quantities have only magnitude and no direction.

In a series circuit, resistors are connected end-to-end, forming a single path for current.

The solar constant ($S$) is the average intensity of solar radiation received at the top of Earth’s atmosphere, measured perpendicular to the incoming rays.

The specific heat capacity $c$ of a substance is the energy required to raise the temperature of 1 kg of the substance by 1 K.

Specific latent heat $L$ is the energy required to change the phase of 1 kg of a substance at constant temperature.

Spontaneous fission occurs when a heavy nucleus splits into smaller nuclei without any external influence.

Standing wave is a combination of two waves moving in opposite directions, each having the same amplitude and frequency.

Stellar parallax refers to the apparent shift in the position of a nearby star against the background of distant stars when observed from two opposite points in Earth’s orbit around the Sun, six months apart.

The stopping voltage is the voltage required to repel all emitted electrons, stopping the current.

Terminal velocity is the constant speed an object reaches when the drag force equals the gravitational force acting on it.

The First Postulate: The Principle of Relativity

The laws of physics are the same in all inertial reference frames.

The half-life $T_{1/2}$ is the time it takes for half of the radioactive nuclei in a sample to decay.

The law of conservation of momentum states that the total momentum of an isolated system remains constant if no external forces act on it.

The second law of thermodynamics states that in any natural process, the total entropy of an isolated system always increases or remains constant in ideal reversible processes.

The Second Postulate: The Constancy of the Speed of Light

The speed of light in a vacuum is the same for all observers, regardless of the motion of the light source or the observer.

The strong nuclear force is one of the four fundamental forces of nature and is responsible for holding the nucleus together. It acts between all nucleons (protons and neutrons).

The work-energy theorem states that the net work done on an object is equal to the change in its kinetic energy.

A thermistor is a resistor whose resistance changes with temperature.

The threshold frequency $f_{\text{c}}$ is the minimum frequency of light required to eject electrons.

Time dilation is the phenomenon where time passes more slowly for an observer in motion relative to a stationary observer.

Torque is the rotational equivalent of force. It measures the ability of a force to cause an object to rotate.

A transformer is a device that changes the voltage of an alternating current (AC) using the principles of electromagnetic induction.

An object is in translational equilibrium when the sum of all the external forces acting on the object equals zero.

A trough is the lowest point of a wave, where the displacement of the medium is at its maximum negative value relative to the equilibrium position. In a transverse wave, troughs correspond to the lowest points in the wave motion.

Variable resistors are components that allow you to adjust the resistance in a circuit.

Vector quantities have both magnitude and direction.

A wavefront is an imaginary surface that connects points on a wave that are in phase (i.e., at the same point in their oscillation cycle).

Waves are disturbances that transfer energy from one place to another without transferring matter.

Work is defined as the product of the force applied to an object, the displacement of the object, and the cosine of the angle between the force and the displacement.

Work function $\phi$ is the minimum quantity of energy which is required to remove an electron from the surface of a given solid.

A worldline is the path an object traces in spacetime.