NDA GK Questions 2026

Quartz is crystalline silicon dioxide (SiO₂), an electrical insulator, not a semiconductor. A semiconductor has a conductivity between that of a conductor and an insulator, and its conductivity rises with temperature or when impurities are added (doping).

With equal length and area, the wire of lower conductivity, aluminium, has the higher resistance. Resistance is R = ρl/A, where ρ is resistivity, and resistivity is the reciprocal of conductivity (ρ = 1/σ).

A candle gives light by burning wax, so it converts chemical energy, not electrical energy, into light and heat. In a burning candle the wax vapour combines with oxygen in the air; the chemical energy stored in the wax is released as heat and light.

The black layer on old silver is silver sulphide (Ag₂S). Air contains traces of sulphur compounds, mainly hydrogen sulphide (H₂S) from burning fuels and decaying matter.

Bauxite, a hydrated aluminium oxide (Al₂O₃·2H₂O), is the main ore from which aluminium is extracted. Bauxite is first purified into alumina (aluminium oxide) by the Bayer process.

A guard tube is filled with anhydrous calcium chloride, which absorbs moisture and keeps the hydrogen chloride gas dry. In the school experiment, hydrogen chloride gas is made by heating sodium chloride with concentrated sulphuric acid, and the gas is passed through a guard tube containing calcium chloride.

The gastric glands in the stomach wall secrete hydrochloric acid, the only mineral (inorganic) acid among the options. Hydrochloric acid (HCl) makes the stomach strongly acidic, with a pH of about 1.5 to 3.5.

Pitch is the way our ear senses the frequency of a sound: the higher the frequency, the higher the pitch.

When houses are built all around a lake or tank, the village grows in a ring around the water, giving a circular pattern.

The Office of the United Nations High Commissioner for Refugees won the Nobel Peace Prize in 1954 and again in 1981.

A rainbow forms only because sunlight is refracted, dispersed and internally reflected inside raindrops. When sunlight enters a water droplet it is refracted and split into its colours (dispersion), because each colour bends by a different amount.

Both a plane mirror and a convex mirror always form an erect, virtual image, whatever the distance of the object.

Iron is a transition (d-block) element, and such elements can show more than one oxidation state. In transition metals the energies of the outer s electrons and the inner d electrons are very close, so atoms can lose different numbers of electrons.

Helium is a noble gas whose atoms exist singly, so it is a monatomic gas, not a diatomic one. Helium has a completely filled first shell (1s²), so its atoms have no tendency to share electrons or bond with each other.

While speaking about the strategic value of Karwar, the Vice-President pointed to the ongoing development of modern naval infrastructure under Project Seabird, which is raising the Navy's capacity to base and maintain its ships and submarines and is also generating wider economic opportunities in the region.

The commissioning ceremony was held at Karwar, and the Vice-President used the occasion to explain why the location matters: Karwar has a deep natural harbour and lies close to the Arabian Sea, which makes it an important element of India's maritime security architecture.

The vessel was commissioned by Vice-President C. P. Radhakrishnan at Karwar in Karnataka and is described as the Indian Navy's first indigenous Multi-Purpose Vessel, with more than 75 per cent of its content made in India.

CL-20, HMX and LLM-105 are all powerful high explosives used in warheads, shells and military charges. HMX, also called octogen, is a nitramine explosive more powerful than RDX and is used in missile warheads and shaped charges.

The correct answer is the Minister for Youth Affairs and Sports, Dr Mansukh Mandaviya, who hosted the visiting Polish delegation over dinner in New Delhi and spoke with them about how India approaches youth development and participation.

The Balachadi memorial commemorates the shelter, schooling and medical care that Maharaja Jam Saheb Digvijaysinhji Ranjitsinhji Jadeja provided to Polish children displaced during the Second World War, and the visiting delegation treated it as the high point of the week.