General Science Mixed Quiz: Set 112

Pulling the hands back stretches the time in which the ball stops, so its deceleration and the force on the hands become smaller.

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.

For any real object, a convex mirror forms a virtual, erect and smaller image behind the mirror, between the pole and the focus.

Meiosis makes gametes that differ from one another, and fertilization joins a gamete from each of two parents, so every offspring gets a new mix of genes.

Outside a long straight wire, the field is B = μ₀I/(2πr), so doubling the distance halves the field. This result follows from Ampère's circuital law, or from the Biot–Savart law applied to a long wire.

Above the threshold, the kinetic energy of the ejected electrons rises as the frequency of the light rises, so the statement that it does not change is wrong.

Iron is a transition (d-block) element, and such elements can show more than one oxidation state. In transition metals the energies of the outer s electrons and the inner d electrons are very close, so atoms can lose different numbers of electrons.

The velocity ratio of a pulley system is the distance moved by the effort divided by the distance moved by the load, so it is 12 divided by 3, that is 4.

Potassium and barium exchange their partner ions: K₂SO₄ and BaCl₂ swap ions to give KCl and BaSO₄. In a double displacement reaction two compounds exchange ions.

Temporary hardness comes from dissolved calcium and magnesium hydrogencarbonates (bicarbonates), and it can be removed simply by boiling. On boiling, calcium hydrogencarbonate breaks down into insoluble calcium carbonate, water and carbon dioxide, and the carbonate settles out; this is the scale seen inside kettles.

The stinging hairs on nettle leaves inject methanoic acid, also called formic acid, into the skin, which causes the burning pain.

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.

The black layer on old silver is silver sulphide (Ag₂S). Air contains traces of sulphur compounds, mainly hydrogen sulphide (H₂S) from burning fuels and decaying matter.

Pollen first reaches the stigma, then the gametes fuse, the zygote divides to form an embryo, and the embryo inside the seed grows into a seedling.

Brine is a concentrated solution of common salt, sodium chloride (NaCl), in water. Brine occurs naturally in seawater, salt lakes and underground deposits.

To just complete a vertical circle, a bob on a string needs a speed of at least √(5gL) at the lowest point, and √(5 × 10 × 0.5) = √25 = 5 m/s. A string can only pull, never push.

Prokaryotic cells, such as bacteria, have no true nucleus; their DNA lies free in the cytoplasm in a region called the nucleoid.

Digestion begins in the mouth, where saliva adds salivary amylase to the food as it is chewed. Salivary amylase, also called ptyalin, starts breaking starch into maltose while food is still in the mouth.

Urea is the form in which the body gets rid of the nitrogen left over when amino acids from proteins are broken down.

Too little fluoride weakens tooth enamel and makes teeth prone to decay, known as dental caries. Fluoride becomes part of the enamel as fluorapatite, which resists the acids made by mouth bacteria from sugars.