General Science Mixed Quiz: Set 152

Standard atmospheric pressure at sea level is defined as the pressure of a 760 mm column of mercury at 0 °C. In 1643 Evangelista Torricelli showed that air pressure holds up a column of mercury about 760 mm (76 cm) tall in a glass tube, inventing the mercury barometer.

Ornithology is the study of birds, their classification, habits, migration and nesting; Salim Ali, known as the birdman of India, was the country's best known ornithologist and wrote the Book of Indian Birds.

Statements 1 and 3 describe real differences; statement 2 gets the life span backwards. A sodium vapour lamp is a glowing tube that sends light out in all directions, through 360 degrees, so reflectors are needed to push the light down onto the road and some light is wasted.

A beam seen from the side is visible only because tiny particles send some of its light sideways. Light travelling in a straight line cannot enter our eyes unless something redirects it towards us.

Both beams carry conventional current in the same direction, north to south, and parallel currents in the same direction attract each other.

Anabaena is a cyanobacterium, a prokaryote with no true nucleus, and all prokaryotes are placed in Monera. In R.H.

In graphite each carbon atom is sp² hybridised, not sp³, so statement A is the one that is not true.

A lactometer floats in milk and shows its relative density. Pure milk is denser than water, so adding water lowers the density and the instrument sinks deeper, which reveals the adulteration.

In long-sightedness (hypermetropia) the eye cannot see nearby objects clearly because their image is formed behind the retina.

The correct answer is B, the cerebellum, which lies below and behind the cerebrum and coordinates the work of the muscles so that movement is smooth and the body stays balanced; this is why a person whose cerebellum is affected by alcohol staggers.

A hydrogen bomb fuses light hydrogen nuclei, while a uranium bomb splits heavy uranium-235 nuclei. In nuclear fission a heavy nucleus such as uranium-235 absorbs a neutron and splits into two lighter nuclei, releasing energy and two or three more neutrons.

Elektron is the Greek name for amber, the fossilised tree resin which the ancient Greeks found would attract straw, feathers and bits of dust after being rubbed with fur.

The base is made thin and lightly doped so that most charge carriers from the emitter cross it to the collector.

Heating a liquid makes its molecules move faster and sit a little further apart, so the attraction between them weakens, and both properties depend on that attraction.

Stainless steel is an alloy of iron with chromium and usually nickel and a little carbon; tin is not one of its components.

A p-n junction conducts freely in forward bias, where the potential barrier is reduced, and blocks current in reverse bias, where only a tiny leakage current flows.

Both statements swap the two scales: octane number rates petrol, cetane number rates diesel, and their reference fuels are the other way round.

Rhizopus, the bread mould, feeds on dead and decaying organic matter, which is exactly what a saprophyte does. A saprophyte gets its food by releasing digestive enzymes onto dead matter such as stale bread, fruit or leaf litter and then absorbing the simple nutrients that result.

Monkeys are primates, and female primates have a menstrual cycle, not an oestrus cycle.

When water is short, leaves make more abscisic acid (ABA), which makes the guard cells lose water and close the stomata, so the plant loses less water through transpiration.