General Science Mixed Quiz: Set 103

A body in equilibrium has no net force and no net moment on it, while neither momentum nor kinetic energy is conserved in every situation.

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.

Electric power is voltage multiplied by current, and 110 V × 0.2 A = 22 W. Power is the rate at which electrical energy is used.

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.

The weight we feel is really the push of the floor on us, and in orbit that push disappears. The space station and the astronaut are both in free fall around the Earth.

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).

A thermocouple has no liquid that can freeze, so suitable types can read temperatures far below −200°C. A thermocouple is made of two wires of different metals joined at a junction.

Groundnut, horse-gram and soybean are all legumes of the family Fabaceae (Leguminosae), the pea family. Members of the pea family bear their seeds in pods and carry root nodules in which Rhizobium bacteria fix atmospheric nitrogen.

Light travels at different speeds in different media, and this change in speed at the boundary makes it bend. Light is fastest in vacuum, about 3 × 10⁸ m/s, and slower in water and glass.

Pinctada margaritifera is the black lip pearl oyster, a bivalve mollusc of the warm shallow water of the Indo-Pacific, where it fastens itself to coral reefs by strong threads.

Pitch is how the ear perceives the frequency of a sound, so a higher pitch means more vibrations per second.

The velocity ratio of a pulley system is the distance moved by the effort divided by the distance moved by the load, so it is 12 divided by 3, that is 4.

Resistivity is a property of the material itself, so it stays the same when the length of the wire is changed.

Together the two resins take out every dissolved ion, which leaves demineralised water. In the cation exchange resin (written RH), metal ions such as Ca2+, Mg2+ and Na+ are swapped for H+ ions.

Both have 10 electrons, the same number as a neon atom, so they are isoelectronic. Isoelectronic species have the same number of electrons.

The middle ear holds three tiny bones, the smallest in the human body, called the malleus, the incus and the stapes, which in everyday English are the hammer, the anvil and the stirrup.

The stinging hairs on nettle leaves break on touch and inject methanoic acid, also called formic acid, into the skin, which causes the burning pain.

Magnesium does not react with cold water; it reacts with hot water and burns in steam to form magnesium oxide and hydrogen.

Coal is an impure fossil fuel containing hydrogen, oxygen, nitrogen and sulphur besides carbon, so it is not a pure form of the element.

This is the false statement: glass cools into an amorphous solid without any regular crystal structure. When molten glass cools, its viscosity rises so quickly that the atoms have no time to arrange themselves in an ordered crystal lattice.