Practice MCQ Questions and answers on Physics-GK

Natural radioactivity was discovered by Henri Bacquerel.

The fuel that is used in a nuclear reactor to maintain a nuclear concatenation response is known as Nuclear fuel. These fuels are fissionable, and the most popular nuclear combustibles are radioactive elements such as uranium-235 and plutonium-239.

Alpha particle is the nucleus of an atom of Helium.

Nuclear energy is energy stored in the nucleus of an atom; it is the energy that holds the nucleus together.

Moderator is required in a Nuclear reactor to slow down the neutrons produced during the fission reaction so that the chain reaction can be sustained. Heavy Water is an excellent moderator due to its high moderating ratio and low absorption cross section for neutrons.

Radioactive elements can be traced out in living cell through a technique called Autoradiography.

The parts of the electromagnetic spectrum, arranged from highest energy to lowest, are gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves.

The light in sodium vapour lamp and mercury vapour lamp is, because of electron emission. In case of Sodium Lamps, filaments of the lamp sputter fast moving electrons, which hit the sodium atoms (vapour) causing the valence electrons of the sodium atoms to excite to higher energy levels and the electrons thus excited relax by emitting the characteristic monochromatic bright yellow light. The mechanism in mercury vapour lamp is more involved and sequential. The sputtered electrons from the filaments, after having been accelerated by high voltage, hit the mercury atoms. Here also, the excited electrons of mercury atoms relax by emitting characteristic but ultraviolet light.

Nuclear Reactors uses Controlled Nuclear Fission to generate electricity. A nuclear reactor splits the atoms of nuclear fuel (eg. uranium) to generate energy to turn water into steam to drive turbine generators.

There are three types of nuclear radiation: alpha, beta and gamma. Alpha is the least penetrating, while gamma is the most penetrating.