Test: Radioactivity - Class 10 MCQ

The mass-energy equivalence formula proposed by Einstein is E = mc², which states that energy (E) is equal to mass (m) times the square of the speed of light (c). This principle indicates that mass can be converted into energy.

Isobars are defined as atoms of different elements that have the same mass number but different atomic numbers. This means they have the same total number of nucleons but differ in the number of protons.

In nuclear fission, a heavy nucleus splits into two lighter nuclei when bombarded with neutrons, releasing a significant amount of energy in the process.

Beta particles are fast-moving electrons emitted from the nucleus during radioactive decay. They differ from cathode rays, which are emitted from orbital electrons.

Carbon dating is used to estimate the age of organic materials, such as rocks or fossils, by measuring the rate of decay of carbon-14, a radioactive isotope.

Atoms that belong to the same element but have different mass numbers are called isotopes. They have the same number of protons but a different number of neutrons.

Gamma radiation consists of electromagnetic waves, similar to X-rays and light, and is not deflected by electric and magnetic fields due to its neutral charge.

A common safety precaution for handling radioactive materials is the use of lead shielding. Lead is effective at blocking various types of radiation, thus protecting personnel from exposure.

The first shell of an atom can accommodate a maximum of 2 electrons. This is a fundamental principle of atomic structure, reflecting the arrangement of electrons in shells.

Radioactive isotopes are not used in fertilizer production. Their applications include cancer treatment, medical diagnostic tracers, and thickness measurement in various manufacturing processes.

Alpha decay involves the emission of an alpha particle, which consists of two protons and two neutrons. This type of decay reduces the atomic number of the element.

Neutrons are uncharged particles found in the nucleus of an atom, and they contribute to the mass number (the total count of protons and neutrons) of the element.

During beta decay, the atomic number of the element increases by one because a neutron is converted into a proton, resulting in a new element with one more proton in its nucleus.

The maximum number of electrons that can be accommodated in the third shell is 18. This is based on the formula 2n², where n is the shell number.

Alpha particles are the most effective at ionizing materials due to their higher mass and charge. They can strongly affect the medium they pass through, ionizing atoms and molecules effectively.

The primary distinction lies in the use of moderators. A controlled chain reaction uses moderators to absorb some neutrons, regulating the reaction, while an uncontrolled chain reaction leads to a rapid, explosive release of energy.

Alpha particles are the least penetrating due to their larger mass and charge. They can be stopped by a sheet of paper or even the outer layer of human skin.

The purpose of a moderator in a nuclear reactor is to absorb some of the neutrons emitted during fission, thus controlling the chain reaction and allowing for a steady release of energy.

The phenomenon of radioactive substances emitting radiation is known as radioactive decay. This process occurs when unstable nuclei lose energy by emitting radiation.

The primary component of an atom that carries a positive charge is the proton. It is located in the nucleus of the atom and contributes to the atomic number, which defines the element.