General Science Mixed Quiz: Set 54

A catalytic poison is a substance that lowers or destroys the activity of a catalyst, usually because it sticks firmly to the active surface and leaves no room for the reactants.

Hooke's law holds only as far as the limit of proportionality, and that limit is either equal to or lower than the elastic limit, so statements 1 and 4 are the correct pair.

Bacillary dysentery, also called shigellosis, is caused by bacteria of the genus Shigella, which invade the lining of the large intestine and produce frequent stools with blood and mucus, along with fever and cramps; it spreads through contaminated water and food.

Pisciculture is the rearing of fish in ponds, tanks and other managed waters, the Latin word piscis meaning fish.

Chlorophyll is built on a ring structure with a single magnesium atom held at its centre, and because magnesium is needed to make the pigment, a plant short of magnesium develops chlorosis, the yellowing of leaves between the veins.

Galileo was the first to argue that, with air resistance removed, every body falls with the same acceleration regardless of its mass.

Milk is an emulsion because it is tiny drops of liquid fat spread through water, and an emulsion is a colloid in which one liquid is dispersed in another liquid.

In electroplating the article to be coated is made the cathode, the plating metal serves as the anode, and both are dipped in an electrolyte containing a salt of that metal.

The pinna is the outer, visible flap of the ear, and its funnel shape collects sound from the surroundings. Sound gathered by the pinna travels down the ear canal to the tympanic membrane, or eardrum, which starts to vibrate.

Litmus is a purple dye taken from lichens, and in the classification used in school science lichens are placed in Thallophyta, the group of simple plants whose body is an undifferentiated thallus with no true root, stem or leaf.

The tiny pores on the surface of a leaf, found mostly on its lower side, are called stomata. Each stoma is a slit guarded by two bean shaped guard cells, which swell to open it and shrink to close it.

Ultraviolet light is a transverse wave, not a longitudinal one, so this statement is the wrong one. In an electromagnetic wave the electric and magnetic fields vibrate at right angles to each other and to the direction the wave travels, which is the definition of a transverse wave.

Rust of wheat is indeed a fungal disease, caused by species of Puccinia, and it is named from the reddish brown spores that appear in streaks on the leaves and stem.

Balance is controlled by the inner ear, which holds the vestibular apparatus alongside the organ of hearing. It is made of three semicircular canals set at right angles to one another and two small sacs, the utricle and the saccule.

In the light reaction, water absorbed by the roots is split in the presence of light and chlorophyll, a step called photolysis of water or the Hill reaction.

The petiole is the stalk that joins a leaf blade to the stem; it belongs to the leaf, not to the flower, and a leaf without one is called sessile.

A homogeneous mixture has the same composition and properties throughout and no visible boundary between its parts, so a true solution such as salt water qualifies, and so does brass, an alloy of copper and zinc, since alloys are solid solutions.

Four species of Plasmodium commonly infect human beings, of which Plasmodium falciparum is the most dangerous and Plasmodium vivax the most widespread in India.

Here the ATP and NADPH made in the light reaction are spent on fixing carbon dioxide into carbohydrate.

This mosquito, marked by white stripes on a dark body, bites during the day and breeds in clean stored water in coolers, tyres and flower pots, which is why dengue control campaigns concentrate on emptying household containers.