General Science Mixed Quiz: Set 149

Most carbon compounds are poor conductors of electricity, because their atoms are joined by covalent bonds and they do not form ions or free electrons that could carry a current.

Herpetology is the study of reptiles such as snakes, lizards, crocodiles and turtles, together with amphibians such as frogs, toads and salamanders, and in India it includes the work on snake venom and antivenom at institutions that maintain snake parks.

In a wheelbarrow the wheel acts as the fulcrum, the load sits in the tray between the wheel and the hands, and the effort is applied at the handles, which is the arrangement of a second class lever; because the effort arm is always longer than the load arm, its…

The correct answer is B, the thyroid gland, a butterfly-shaped gland in front of the windpipe in the neck, which is the largest purely endocrine gland in the body and secretes thyroxine, triiodothyronine and calcitonin.

Alum, that is aluminium sulphate or potash alum, is a coagulant: in water it forms a gelatinous hydroxide that gathers the fine clay and colloidal particles into heavier flocs, which then settle in the sedimentation tank and are removed, leaving clear water for filtration.

Vitamins fall into two groups: the water-soluble ones, which are vitamin C and the whole B-complex, and the fat-soluble ones, A, D, E and K. Vitamin C is ascorbic acid, found in citrus fruits, amla, guava and tomatoes; its deficiency causes scurvy, with bleeding gums and slow healing of wounds.

In a pair of tongs the joint is the fulcrum, the hand presses somewhere in the middle of the arms and the object held lies at the far end, so the effort is between the fulcrum and the load; the effort arm is shorter than the load arm, the mechanical…

Working independently in the 1830s, Michael Faraday in England and Joseph Henry in the United States showed that a changing magnetic flux through a circuit sets up an electromotive force in it, and that the effect depends on the rate of change of flux rather than on the flux itself.

Bleaching powder is prepared by passing chlorine over dry slaked lime and is written as calcium oxychloride; in water it releases chlorine, which kills bacteria and other pathogens, and that is why it is used both for disinfecting water supplies and for bleaching cloth and paper.

This is the statement that is not correct, because water has a much higher surface tension than ethyl alcohol.

In a single fixed pulley the rope that is pulled down moves exactly as far as the load rises, so the distance moved by the effort equals the distance moved by the load and the velocity ratio is one; the pulley gives no gain in force and is used only…

Silicon is the most widely used semiconductor and its forbidden energy gap, the separation between the top of the valence band and the bottom of the conduction band, is about 1.1 electron volts at room temperature.

In reverse osmosis the water is pushed through a semi-permeable membrane at a pressure greater than its osmotic pressure, so the flow runs opposite to natural osmosis; the membrane lets water molecules through and holds back dissolved salts, heavy metals and most microbes, which is why reverse osmosis is also…

Cinnabar is mercuric sulphide, HgS, and the formula itself gives the answer away because Hg is the symbol of mercury.

The velocity ratio of an inclined plane is the length of the slope divided by its vertical height, because the load is pushed along the whole slope while it is raised only through the height; here ten divided by two gives five, so in the ideal case an effort of…

Nylon-6,6 is a polyamide formed when hexamethylenediamine condenses with adipic acid, with a molecule of water eliminated at each linkage; the name records that each monomer contributes a chain of six carbon atoms.

A moderator slows down the fast neutrons released by fission so that they can cause further fission, and heavy water is the best of them because it slows neutrons well while absorbing very few; in Indian pressurised heavy water reactors it also serves as the coolant that carries heat away…

The pitch of a screw is the distance between two consecutive threads measured along its axis, and it is also the distance through which the screw advances in one complete turn; the velocity ratio of a screw is the circumference of the circle described by the handle divided by the…

Soap is the sodium or potassium salt of a long chain fatty acid.

A wedge is two inclined planes joined back to back, and an axe, a knife, a chisel and a nail all work on that principle: a force applied at the blunt end is turned into a much larger sideways force at the sharp edge, and the thinner and longer the…