Modern Physics - SS1 Physics Past Questions and Answers - page 1

Quantum mechanics is a branch of modern physics that describes the behaviour of particles at the atomic and subatomic levels. It is based on the principle of wave-particle duality, which states that particles, such as electrons and photons, can exhibit both wave-like and particle-like properties. The key concepts in quantum mechanics include wave functions, probability amplitudes, superposition, and the uncertainty principle.

Wave functions describe the quantum state of a particle, and the square of the wave function gives the probability density of finding the particle in a particular state. Superposition refers to the ability of particles to exist in multiple states simultaneously until observed or measured. Overall, quantum mechanics revolutionised our understanding of the microscopic world, challenging classical physics and providing a foundation for various technological advancements.

The theory of relativity, developed by Albert Einstein, postulates that the laws of physics are the same for all observers in uniform motion and that the speed of light is constant in all inertial reference frames. This theory led to remarkable consequences, such as time dilation, length contraction, and the famous equation E=mc², which relates energy and mass.