General Science Mixed Quiz: Set 129

On a frictionless surface the person can move only by throwing something out in one direction, and a sneeze pushes air forward so the body recoils backward.

Red blood cells are produced in the red bone marrow, lose their nucleus on maturing and survive roughly four months, after which they are broken down in the spleen, which is accordingly called the graveyard of red blood cells; the iron released from their haemoglobin is used again.

When the force acts opposite to the displacement, the angle between them is 180°, and work W = F d cos 180° = −F d. Work done by a force is the product of the force, the displacement and the cosine of the angle between them.

The 2011 FSSAI labelling rules made the list of ingredients, nutrition information and the vegetarian or non-vegetarian mark compulsory, but not medical advice on allergies.

Weight is the gravitational force with which the Earth pulls an object towards its centre. Weight is given by W = mg, where m is the mass and g is the acceleration due to gravity, about 9.8 m/s² near the Earth's surface.

Meiosis halves them in the gametes, and fertilisation restores them in the offspring. Each parent makes gametes by meiosis, so a human egg or sperm carries 23 chromosomes instead of 46.

In 5 seconds the sound travels to the mountain and back, a total of 340 × 5 = 1,700 m, so the mountain is half of that, 850 m or 0.85 km, away.

The spring constant is force divided by extension, so its SI unit is newton per metre. Hooke's law says that, within the elastic limit, the restoring force of a spring is proportional to how far it is stretched or compressed: F = −kx.

The magnetic force depends on the sine of the angle between velocity and field, and sin 90° is the largest value.

Portland cement is made by heating a mix of limestone, which supplies lime, with clay, which supplies silica and alumina.

The number of protons in the nucleus defines an element, and no two elements share it. The atomic number (Z) is the number of protons in an atom's nucleus, and in a neutral atom it also equals the number of electrons, which decide chemical behaviour.

With no external force on the system, its centre of mass cannot start moving. The throw is an internal force: X pushes the tool forward and the tool pushes X backward with an equal and opposite force (Newton's third law).

In each of the four changes a substance combines with oxygen from the air, which is oxidation.

The eri silkworm, Samia ricini, feeds on castor leaves, and its silk is called ahimsa silk because the moth is allowed to emerge before the cocoon is used, leaving a broken fibre that is spun like cotton instead of being reeled.

Orthophosphoric acid, H 3 PO 4, has three replaceable hydrogen ions, so it is tribasic. The basicity of an acid is the number of hydrogen ions one molecule can give up in water.

The formula T₀ = 2π√(L/g) holds only for small swings; at large amplitudes the period grows.

Both are pure forms of carbon, but their atoms are arranged differently, which gives them opposite physical properties. Diamond and graphite are allotropes of carbon.

Solid carbon dioxide is called dry ice because it turns straight into gas without melting into a liquid, so it leaves nothing wet behind.

The animal cell membrane is a phospholipid bilayer with proteins set in it and cholesterol between the lipid molecules. The fluid mosaic model of Singer and Nicolson (1972) describes the membrane as a double layer of phospholipids, whose water-loving heads face outward and water-fearing tails face inward.

Bile breaks fat into tiny droplets and lipase then splits those droplets into fatty acids and glycerol. Bile is made by the liver, stored in the gall bladder and poured into the duodenum.