question 1 is option: A
question 2 is option: A
Explanation to question 1: When an atom undergoes beta decay, a neutron in the nucleus is converted into a proton, and an electron and an antineutrino are emitted. The electron is called a beta particle. The proton remains in the nucleus, increasing the atomic number of the nucleus by one. Therefore, the daughter nucleus will have a different number of protons and will be a different element than the parent nucleus.
The emission of a beta particle means that the mass number of the daughter nucleus is the same as the parent nucleus. However, the daughter nucleus will have a different number of protons, and therefore, a different atomic mass. The mass of the emitted beta particle is negligible compared to the mass of the nucleus, so the daughter nucleus will lose a small amount of mass in the process.
Since the atomic number of the daughter nucleus has changed, its charge will also change. It will either gain or lose charge, depending on whether it has more or fewer protons than the parent nucleus. Therefore, option a is the correct answer.
Explanation to question 2: Light is created when excited electrons in an atom drop to lower energy levels and release energy in the form of photons. This process is called spontaneous emission. When an electron absorbs energy, it jumps to a higher energy level. This process is called excitation. However, when the electron drops back down to a lower energy level, it releases the energy it absorbed in the form of a photon of light.
Option a correctly describes this process, while options b, c, and d describe other processes that can convert energy into light, but not the specific process by which light is created in atoms. Option b describes the absorption of energy by electrons, option c describes the conversion of electrical energy into light, and option d describes the conversion of kinetic energy into potential energy, neither of which directly produces light.