Physics

The SI unit of luminous intensity, which measures the perceived power of light, is the candela. Watt is a unit of power, Pascal is a unit of pressure, and Joule is a unit of energy, so they are incorrect in this context.

Aerodynamics is the branch of physics that studies the forces acting on bodies in motion through the air, such as lift and drag. This makes option C the correct answer.

Mach number is the ratio of an object's speed to the speed of sound in the surrounding medium. Therefore, it is directly related to the speed of sound, not specifically to aircraft, ships, or light.

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction, which is exactly described in option A. The other options describe unrelated physical concepts.

Very High Frequency (VHF) waves have shorter wavelengths compared to lower frequency waves. As frequency increases, wavelength decreases, so VHF waves have shorter wavelengths than lower frequency bands.

One Coulomb is the charge of approximately 6.25×10^18 elementary charges (electrons). This is calculated by dividing 1 Coulomb by the charge of one electron (1.6×10^-19 C).

The neutron was discovered late because it carries no electric charge, making it difficult to detect using methods that rely on electric or magnetic fields. Its neutral charge meant it did not respond to electromagnetic detection techniques used for charged particles like protons and electrons.

Robert Millikan determined the absolute value of the electron's charge through his oil drop experiment, which measured the charge on tiny charged droplets, allowing calculation of the electron's charge magnitude.

Potential difference is defined as the work done in moving a unit charge between two points in an electric circuit, which matches the given definition exactly.

Electromagnetism is a branch of physics that studies the interaction between electric and magnetic fields. It is not a branch of chemistry, so the correct answer is Physics.