General Science Mixed Quiz: Set 111

At uniform speed the net force is zero, so the upward force must equal the skydiver's weight. Weight is mass times the acceleration due to gravity: 60 kg × 9.8 m/s² = 588 N, acting downward.

The 2011 FSSAI labelling rules made the list of ingredients, nutrition information and the vegetarian or non-vegetarian mark compulsory, but not medical advice on allergies.

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.

Meiosis makes gametes that differ from one another, and fertilization joins a gamete from each of two parents, so every offspring gets a new mix of genes.

A temperature in kelvin is the Celsius temperature plus 273 (more exactly 273.15). The Kelvin and Celsius scales have degrees of the same size, so a change of 1 °C equals a change of 1 K; only their zero points differ.

The de Broglie wavelength depends only on momentum, so equal wavelengths mean equal momenta. In 1924 Louis de Broglie proposed that every moving particle has a wave linked to it, with wavelength λ = h/p, where h is Planck's constant and p is the linear momentum.

A plane mirror forms an image behind the mirror where light only seems to come from, with left and right swapped.

A qubit, short for quantum bit, is the basic unit of information in a quantum computer.

A metal filament's resistance rises as it heats up, so the current falls and the resistor gets a smaller share of the voltage.

Testosterone is made by the Leydig cells of the testes and is the main male sex hormone.

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.

Marie Curie discovered radium; the first two pairs have their discoveries swapped. Marie Curie and Pierre Curie discovered the radioactive elements polonium and radium in 1898, and Marie Curie went on to win Nobel Prizes in both physics (1903) and chemistry (1911).

On heating, silver oxide breaks down into silver metal and oxygen, while zinc oxide and magnesium oxide stay unchanged. The reaction is 2Ag₂O → 4Ag + O₂.

This is double fertilisation, a feature found only in flowering plants. The pollen tube carries the two male gametes into the embryo sac.

The stinging hairs of the nettle plant inject methanoic acid, also called formic acid, into the skin. Each nettle hair is a fine, brittle tube that breaks on touch and pushes its contents into the skin like a tiny needle.

Capra hircus is the scientific name of the domestic goat, in which Capra is the genus and hircus the species, written in the two-word form that Carl Linnaeus gave to biology.

Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas: Zn + H2SO4 gives ZnSO4 + H2.

This is the statement that is not correct; the other three describe the benzene molecule correctly, and UPSC's official key also gives D. Benzene, C6H6, is a flat ring of six carbon atoms.

Brine is a concentrated solution of sodium chloride, common salt, in water. Brine is the starting point of the chlor-alkali process: passing electricity through it gives sodium hydroxide, chlorine gas and hydrogen gas, which is why the process is named after chlorine and alkali.

Bacteria have peptidoglycan walls and animal cells have no wall, but fungal walls are made of chitin, not cellulose. Statement 1 is correct: peptidoglycan, also called murein, is a mesh of sugars cross-linked by short peptides; penicillin works by blocking its formation.