Physics

Beta particles ionize atoms primarily through direct collisions with the electrons in the atoms. As high-energy electrons (or positrons), beta particles transfer part of their kinetic energy to orbital electrons during inelastic collisions, knocking these electrons out of the atom and causing ionization. This ionization is not mainly due to electrostatic attraction or repulsion but due to the energy transfer in collisions. Gravitational forces are negligible at atomic scales and do not contribute to ionization by beta particles.

Nuclear forces, also known as strong nuclear forces, act between all nucleons—protons and neutrons—inside the nucleus. Therefore, they exist between proton-proton, proton-neutron, and neutron-neutron pairs, making 'All of the above' the correct answer.

During the fusion of hydrogen into helium, nuclear reactions convert mass into energy, releasing a significant amount of energy. This is why stars, including the Sun, emit energy through fusion.

When nitrogen is bombarded with alpha particles, a nuclear reaction occurs producing an oxygen isotope and a proton. This is a classic example of a nuclear reaction where an alpha particle (helium nucleus) collides with nitrogen, ejecting a proton.

Pair production requires the presence of a nearby nucleus or particle to conserve momentum. In a vacuum, momentum cannot be conserved during pair production, so it cannot occur there.

Random errors arise from unpredictable fluctuations in measurement and can be minimized by taking the mean of several measurements, which averages out the random variations.

Torque is defined as the product of force and the perpendicular distance from the axis of rotation (lever arm). Force has the dimension [MLT^{-2}] and distance has the dimension [L]. Therefore, the dimension of torque is the product of these, which is [ML^2T^{-2}]. This matches option A. Option B corresponds to the dimension of force, not torque.

Robert Millikan determined the charge of an electron through his famous oil drop experiment, which measured the elementary electric charge accurately.

Gamma rays (γ-rays) have the highest penetrating power among the listed types of radiation because they have the shortest wavelength and highest energy, allowing them to penetrate materials more deeply than X-rays or beta rays.

A mass spectrograph (or mass spectrometer) sorts out ions based on their mass-to-charge ratio, allowing the identification and analysis of different ions in a sample.