PMS 2026 GK Practice Set - 1000 One-Liners, Q801-850 (Nuclear & Energy, Electricity & Magnetism, Light & Waves, Gas Laws, Atomic Structure) Solved MCQs

Correct Answer: Alpha, Beta, Gamma radiation

Radioactive elements emit alpha, beta and gamma radiation: the three standard types of nuclear radiation from unstable nuclei.

Correct Answer: Energy by splitting heavy nuclei

Nuclear fission produces energy by splitting heavy nuclei: a heavy nucleus splits into lighter nuclei, releasing energy.

Correct Answer: Energy by combining light nuclei

Nuclear fusion produces energy by combining light nuclei: light nuclei fuse into a heavier nucleus, releasing energy, as in the Sun.

Correct Answer: Conversion of sunlight into electricity

Solar energy is the conversion of sunlight into electricity: photovoltaic cells turn sunlight directly into electrical energy.

Correct Answer: Electricity from water flow

Hydropower generates electricity from water flow: flowing or falling water drives turbines that generate electricity.

Correct Answer: Chemical energy

Batteries store chemical energy: chemical reactions inside the cell are converted into electrical energy when the battery is used.

Correct Answer: Flow of electrons

Electric current is the flow of electrons: in a metallic conductor, electrons moving through the wire carry the current.

Correct Answer: Electric potential difference

Voltage is electric potential difference: the energy per unit charge that drives current around a circuit.

Correct Answer: Opposition to current

Resistance is opposition to current: it measures how much a material resists the flow of electric current.

Correct Answer: Flow of electricity

Insulators prevent the flow of electricity: they have no free charge carriers, so current cannot pass through them easily.

Correct Answer: Ferromagnetic materials

A magnet attracts ferromagnetic materials: iron, nickel, cobalt and their alloys are strongly attracted to a magnet.

Correct Answer: Straight line

Light travels in a straight line: in a uniform medium, light moves along straight rays.

Correct Answer: Smooth surface

Reflection of light occurs at a smooth surface: a smooth, polished surface gives regular (specular) reflection, forming a clear image.

Correct Answer: Bending of light in different medium

Refraction is the bending of light in a different medium: light changes speed and direction when it passes from one medium into another.

Correct Answer: Convex lens

A lens converges light in a convex lens: a convex lens brings parallel rays together to a focus.

Correct Answer: Concave lens

A lens diverges light in a concave lens: a concave lens spreads parallel rays apart as if from a virtual focus.

Correct Answer: Number of oscillations per second

Frequency of a wave measures the number of oscillations per second: it is counted in hertz (Hz).

Correct Answer: Distance between successive peaks

Wavelength is the distance between successive peaks: the length of one complete wave cycle, crest to crest.

Correct Answer: 3 x 10^8 m/s

Speed of light in vacuum is 3 x 10^8 m/s: the standard one-liner value for c.

Correct Answer: Interference of light

Newton's rings relate to interference of light: the concentric rings arise from interference between light reflected from two surfaces of a thin air film.

Correct Answer: Angle of incidence = angle of reflection

The law of reflection states that the angle of incidence = angle of reflection: both angles are measured from the normal to the surface.

Correct Answer: P proportional to 1/V at constant T

Boyle's law states P is proportional to 1/V at constant T: at fixed temperature, the pressure of a fixed mass of gas varies inversely with its volume.

Correct Answer: V proportional to T at constant P

Charles's law states V is proportional to T at constant P: at fixed pressure, the volume of a fixed mass of gas varies directly with its absolute temperature.

Correct Answer: Equal volumes of gases have equal molecules at same T&P

Avogadro's law states equal volumes of gases have equal molecules at same T&P: at the same temperature and pressure, equal volumes of gases contain equal numbers of molecules.

Correct Answer: PV = nRT

The ideal gas equation is PV = nRT: pressure times volume equals the number of moles times the gas constant times absolute temperature.

Correct Answer: Mass of one mole of substance

Molar mass is the mass of one mole of substance: the mass, in grams, of 6.022 x 10^23 particles of that substance.

Correct Answer: Pascal (Pa)

Gas pressure unit is the pascal (Pa): the SI unit of pressure, one newton per square metre.

Correct Answer: Joule (J)

Energy unit is the joule (J): the SI unit of energy and work.

Correct Answer: Newton (N)

Force unit is the newton (N): the SI unit of force, the force that gives a 1 kg mass an acceleration of 1 m/s^2.

Correct Answer: Joule (J)

Work unit is the joule (J): work done, like energy, is measured in joules.

Correct Answer: Protons, neutrons & electrons

An atom consists of protons, neutrons and electrons: protons and neutrons form the nucleus, electrons move around it.

Correct Answer: Same protons, different neutrons

Isotopes have the same protons but different neutrons: atoms of the same element with different mass numbers.

Correct Answer: Same mass number, different atomic number

Isobars have the same mass number but different atomic number: atoms of different elements whose total nucleon count is equal.

Correct Answer: 1/12 mass of carbon-12 atom

Atomic mass unit is 1/12 mass of a carbon-12 atom: the standard unit for atomic and molecular masses.

Correct Answer: Distribution of electrons in shells

Electron configuration shows the distribution of electrons in shells: how the atom's electrons are arranged in energy levels around the nucleus.

Correct Answer: Combining capacity of element

Valency is the combining capacity of an element: the number of bonds an atom can form with other atoms.

Correct Answer: Chemically inert elements

Noble gases are chemically inert elements: with full outer electron shells, they rarely form compounds.

Correct Answer: Down the group

Reactivity of alkali metals increases down the group: the outer electron is lost more easily as the atom gets larger down Group 1.

Correct Answer: Down the group

Reactivity of halogens decreases down the group: halogens gain an electron less readily as the atom gets larger down Group 17.

Correct Answer: Dmitri Mendeleev

The periodic table was created by Dmitri Mendeleev: his 1869 table ordered the known elements by atomic weight and left gaps for undiscovered elements.

Correct Answer: Extraction of metals from ores

Metallurgy studies the extraction of metals from ores: the processes by which metals are obtained from their ores and purified.