The mean free path decreases with increasing pressure because more molecules are present in a given volume, leading to more frequent collisions.

The moment of inertia depends on the mass distribution relative to the axis of rotation.

The photoelectric effect requires a minimum threshold frequency; below this frequency, no electrons are emitted regardless of the intensity of the light.

The second law of thermodynamics introduces the concept of entropy, stating that the total entropy of an isolated system can never decrease over time.

A potentiometer is not affected by the internal resistance of the source because it measures voltage by balancing it against a known voltage.

The Wheatstone bridge is primarily used to measure unknown resistances by balancing it against known resistances.

Total internal reflection occurs when light travels from a denser medium to a rarer medium.

A dull black surface is the best emitter of radiation according to Kirchhoff's law of thermal radiation.

A black surface is the best emitter of thermal radiation due to its high emissivity.

The transition from n=2 to n=1 emits the highest energy photon as it involves the largest energy difference.

Electromagnetic waves can travel through a vacuum, while sound waves, water waves, and seismic waves require a medium.

A sound wave is an example of a longitudinal wave, where the particle displacement is parallel to the direction of wave propagation.

Sound waves are mechanical waves that require a medium (solid, liquid, or gas) to propagate, while electromagnetic waves can travel through a vacuum.

Beta decay involves the emission of a beta particle, which is an electron or positron.

The weak nuclear force is mediated by the W and Z bosons.

The photoelectric effect demonstrates the particle nature of light, as it shows that light can be thought of as consisting of particles (photons) that can impart energy to electrons.

The photoelectric effect demonstrates the particle nature of light, as it involves the emission of electrons due to the absorption of photons.

The photoelectric effect demonstrates the particle nature of light, as it shows that light can be thought of as consisting of particles (photons) that can impart energy to electrons.

The emission of electrons in the photoelectric effect demonstrates the particle nature of light, as it involves the transfer of energy from photons to electrons.

The photoelectric effect demonstrates the particle nature of light as it involves photons colliding with electrons.

The splitting of light into two rays in a birefringent material is known as double refraction.

Diffraction is the phenomenon that explains the bending of waves around obstacles and the spreading of waves when they pass through openings.

The Doppler effect describes the change in frequency (and wavelength) of a wave in relation to an observer moving relative to the wave source.

The formation of a rainbow is primarily due to the refraction of light as it enters and exits water droplets in the atmosphere, along with reflection inside the droplets.

Rayleigh scattering is responsible for the polarization of light, especially in the atmosphere, as shorter wavelengths scatter more than longer wavelengths.

Surface tension allows the needle to float on water, as it creates a 'skin' on the surface that can support the weight of the needle.

Capillary action allows liquids to rise in narrow spaces, such as a straw, due to adhesive and cohesive forces.

Surface tension causes small droplets to minimize their surface area, resulting in a spherical shape.

The blue color of the sky is due to Rayleigh scattering, which is a form of polarization.

Refraction occurs when a wave passes from one medium to another and changes speed, resulting in a change in direction.