General Science Mixed Quiz: Set 190

The stretch of a spring is proportional to the force on it, and the weight of the mass on the Moon is one-sixth of its weight on Earth.

This is the taxonomic hierarchy for animals, going from the broadest group down to the most specific. Linnaeus built this ladder of ranks, and each rank contains one or more ranks below it.

Cement needs one calcareous material, limestone, for its lime, and one argillaceous material, clay or shale, for its silica, alumina and iron oxide; the mixture is burnt in a rotary kiln at about 1450 degrees Celsius to give clinker, which is then ground with gypsum.

This bacterium ferments the lactose of milk into lactic acid, and the acid makes the milk protein coagulate, which is why a spoonful of old curd added to warm milk sets the whole vessel.

Torque is the product of the force and the perpendicular distance of its line of action from the axis, so the same turning effect can be produced by a smaller force if that distance is made larger; a long handle therefore does the same work with less effort.

A muscle contracts when calcium ions are released from the sarcoplasmic reticulum, and it relaxes when they are pumped back into it.

Metal oxides dissolved in molten glass absorb part of the visible spectrum, and cobalt oxide is the standard colourant for the deep blue of bottles and decorative glass, effective in very small quantities.

It is caused by a virus that stays latent in the nerve cells for life, so the attacks can be controlled with medicines but the infection cannot be completely cured; hepatitis B and HIV infection fall in the same group.

A zero net force gives translational equilibrium, so the body as a whole does not accelerate, and a zero net torque gives rotational equilibrium, so it does not begin to spin; complete equilibrium requires the two together.

On meeting an antigen a B lymphocyte multiplies and turns into a plasma cell, which pours out antibodies, that is immunoglobulins, into the blood; this arm of the defence is called humoral immunity, while T lymphocytes kill infected cells and regulate the response in cell-mediated immunity.

Replacing part of the soda and lime of ordinary glass with boron trioxide gives a glass whose coefficient of thermal expansion is very low, so it does not crack when heated or cooled suddenly; that is why laboratory beakers, test tubes and ovenware are made of it.

Dolly was a sheep produced at the Roslin Institute in Scotland in 1996 by the technique of somatic cell nuclear transfer, in which the nucleus of an udder cell of one sheep was placed in an egg whose own nucleus had been removed, so the lamb carried the genes of…

In stable equilibrium the original position is the one of least potential energy, so a small displacement lifts the centre of gravity and the weight of the body brings it back, as with a cone resting on its base or a book lying flat on a table.

Saffron is made from the stigmas of the flower of Crocus sativus, and since each flower carries only three stigmas which must be picked by hand, the spice is the most expensive in the world; in India it is grown mainly in the Kashmir valley.

Gun powder, also called black powder, is made of roughly seventy-five parts potassium nitrate or saltpetre, which supplies oxygen, fifteen parts charcoal, which is the fuel, and ten parts sulphur, which lowers the ignition temperature and speeds the burning.

Ohm found that for a metallic conductor at a steady temperature the ratio of potential difference to current is a constant, the resistance, which is written as V equals I into R, so doubling the voltage doubles the current.

In a wheelbarrow the wheel is the fulcrum, the load in the tray lies between the wheel and the hands, and the effort is applied at the handles, so the load sits in the middle, which defines a second class lever; a nutcracker, a bottle opener and a lemon squeezer…

Nobel made the dangerously sensitive liquid nitroglycerine safe to transport and use by absorbing it in kieselguhr, a porous earth, and patented the resulting dynamite in 1867; he later combined nitroglycerine with nitrocellulose to make blasting gelatin, and the fortune from these patents endowed the Nobel Prizes.

A solid cone has more material near its wide base than near its apex, so its centre of gravity lies on the axis of symmetry well below the middle, at one quarter of the height measured from the base, which is three quarters of the height measured down from the…

Muriate of potash is potassium chloride, carrying about sixty per cent potash, and it is the cheapest and most widely used source of potassium for crops; the old word muriate simply means a chloride.