General Science Mixed Quiz: Set 151

Surface gravity is g = GM/R², so doubling the mass doubles g while doubling the radius divides it by four, leaving g₁ × 2/4 = g₁/2.

Mycology is the study of fungi, the group that includes moulds, yeasts, mushrooms and the rusts and smuts that attack crops, and a specialist in it is called a mycologist.

The lemon looks bigger because light from it bends as it passes from water through the curved glass into air.

A true fruit is a ripened ovary and nothing else. After fertilisation, the ovary of a flower develops into the fruit, its wall becomes the pericarp and the ovules inside become seeds.

SONAR sends out pulses of high-frequency sound, above 20 kHz, which travel well through water and bounce back from objects.

Spindle fibres attach to the kinetochore, a disc-shaped protein structure on the centromere of each chromosome. During cell division the spindle, made of microtubules, pulls the copies of each chromosome apart.

By Ohm's law the heater's resistance is 40 V divided by 2 A, which is 20 ohms, so at 140 V it draws 140 divided by 20, or 7 A. Ohm's law states that, at constant temperature, the current through a conductor is directly proportional to the potential difference across…

If pressure is proportional to temperature for a fixed amount of ideal gas, the volume must stay constant, so the process is isochoric.

A single compound, silver chloride, breaks down into two simpler substances, silver and chlorine, which is exactly what a decomposition reaction is.

Crown gall is caused by the bacterium Agrobacterium tumefaciens, which enters through a wound near the base, or crown, of the stem and makes the plant grow rough tumour-like swellings there.

In the list of natural sources of acids that school science teaches, tomato is matched with oxalic acid.

The spring constant is force divided by extension, so its SI unit is newton per metre. Hooke's law says that, within the elastic limit, the restoring force of a spring is proportional to how far it is stretched or compressed: F = −kx.

Ethanol does not change the colour of either red or blue litmus, because it is neutral. Ethanol, C₂H₅OH, is an alcohol.

The slightest push makes the ball fall off and it does not come back. A body is in unstable equilibrium when a small displacement lowers its centre of gravity, so the forces acting on it move it further away instead of back.

Mature sclerenchyma cells have thick walls hardened with lignin and lose their living contents, so they are dead cells that give the plant strength.

The Central Silk Board was constituted under the Central Silk Board Act, 1948 and works under the Ministry of Textiles with its headquarters in Bengaluru, from where it runs the country's sericulture research and seed organisation.

Too little fluoride in drinking water leaves tooth enamel weak, so teeth decay more easily and develop cavities, called dental caries.

ACE2 is the receptor through which the coronavirus SARS-CoV-2, the cause of COVID-19, enters human cells. ACE2 stands for angiotensin-converting enzyme 2, a protein on the surface of cells in the lungs, heart, blood vessels, kidneys and gut, where it normally helps control blood pressure.

Mitochondrial DNA comes only from the mother, and mitochondrial replacement therapy can stop a mitochondrial disease from passing to the child.

The splitting of white light into its seven component colours by a prism is called dispersion. White light is a mixture of colours, and glass bends each colour by a different amount because its refractive index depends on wavelength.