General Science GK Questions with Answers – Page 86

A real, inverted image of the same size forms only when the object sits at twice the focal length of a convex lens, so 2f = 10 cm and f = 5 cm.

Light inside the fibre strikes the boundary at more than the critical angle, so it is reflected back again and again instead of escaping.

A speed radar measures how much the frequency of its reflected wave changes, and that change depends on the speed of the vehicle.

Both kinds of radiation carry energy that food absorbs as heat, and both are used in everyday kitchens. Infrared radiation is the heat radiation given out by hot bodies: a grill, a toaster, an oven element or glowing coals cook the surface of food mainly by infrared rays.

All three are adaptations of desert plants (xerophytes) that cut down water loss through transpiration. Plants lose most of their water through the leaves, so desert plants change their leaves to save it.

Wendell Meredith Stanley crystallised the tobacco mosaic virus and showed that the crystals were made chiefly of protein, work that proved a virus could be handled like a chemical substance and won him a share of a Nobel Prize.

In binomial nomenclature the first word of the name is the generic name, the genus to which the organism belongs, and the second is the specific epithet; thus Panthera is the genus that also holds the lion as Panthera leo and the leopard as Panthera pardus, while tigris is the…

Arthropoda is the largest phylum of the animal kingdom, holding more described species than all the others together, because it contains the insects along with the crustaceans, spiders, scorpions and centipedes; its members have a chitinous exoskeleton and jointed legs.

In a lichen the algal partner, called the phycobiont, photosynthesises and supplies food, while the fungal partner, the mycobiont, gives shelter and absorbs water and minerals; lichens grow on bare rock as pioneers and die in polluted air, so they serve as indicators of air pollution.

Mosses and liverworts grow on damp soil, rocks and tree trunks, that is on land, but they have no vascular tissue and their male gametes must swim through a film of water to reach the female gamete, so reproduction fails without water; living on land and breeding in water is…

Mycoplasmas are the smallest living cells known, they lack a cell wall altogether, and because of that they can change shape and are not affected by antibiotics that act on the wall; they cause diseases in plants and animals and are placed in the kingdom Monera.

The wall of a fungal cell is built of chitin, a nitrogen-containing polysaccharide that is also found in the exoskeleton of insects, and it is one of the main reasons fungi were taken out of the plant kingdom and given a kingdom of their own.

A species is a group of organisms that resemble one another in all essential characters and that can interbreed to produce fertile offspring; it is the smallest and the basic unit of classification, and all higher ranks are built by grouping species together.

Chlamydomonas is a unicellular, flagellated member of the Chlorophyceae, the green algae, in which chlorophyll a and b give the plant its grass-green colour and the food is stored as starch.

Robert Harding Whittaker proposed the five kingdoms Monera, Protista, Fungi, Plantae and Animalia in 1969, using cell structure, body organisation, mode of nutrition, reproduction and evolutionary relationships as the criteria of division.

The Swedish naturalist Carl von Linne, known in Latin as Carolus Linnaeus, arranged plants and animals in a hierarchy of ranks and gave biology the two-word system of scientific names in his works Systema Naturae and Species Plantarum, so he is called the father of taxonomy.

The Sweet Revolution is the term used for the drive to raise honey production and beekeeping in India, supported by the National Beekeeping and Honey Mission.

The correct answer is B, Jharkhand, the leading lac producing state of India, which also explains why the country's lac research institute stands at Namkum near Ranchi.

The silkworm's silk gland secretes a protein called fibroin, and over it a second protein, sericin, which acts as a gum and hardens the cocoon; boiling the cocoon softens the sericin so the filament can be reeled, and removing it afterwards is called degumming, which gives silk its lustre and…

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.