General Science Mixed Quiz: Set 136

By the law of conservation of momentum, the boy and the cart move together with the momentum the boy brought, so their speed is 104 ÷ 55, about 1.89 m/s. With frictionless wheels, no outside horizontal force acts, so total momentum stays the same.

Twelve pairs of cranial nerves arise from the brain and serve the head and neck, among them the optic nerve of sight, the auditory nerve of hearing and the vagus, the longest cranial nerve, which reaches the heart and the abdomen; thirty-one pairs of spinal nerves arise from the spinal…

Potential energy is the energy a body stores because of its position or because its shape has been changed. A body raised to a height h has gravitational potential energy equal to mgh, where m is its mass and g is the acceleration due to gravity.

The Food Safety and Standards Authority of India is the statutory body that lays down standards for food and regulates its manufacture, storage, sale and import across India.

Sound travels through water at about 1,480 metres per second at 20°C, which rounds to 1,500 m/s. Sound is a mechanical wave and needs a medium.

One faraday is the charge carried by one mole of electrons, obtained by multiplying the charge on a single electron by the Avogadro number, and it comes to about 96,500 coulombs; passing one faraday through an electrolyte liberates one gram equivalent of the substance at an electrode.

Charge equals current multiplied by time, and 1.0 A for 600 seconds gives 600 coulombs. Electric current is the rate of flow of charge, so I = Q ÷ t, or Q = I × t. Time must be in seconds: 10 minutes is 10 × 60 = 600 seconds.

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.

Hydrogen bonds lock the molecules of ice into an open cage, so ice takes up more space than the same mass of liquid water.

If pressure is proportional to temperature for a fixed amount of ideal gas, the volume must stay constant, so the process is isochoric.

Aluminium oxide reacts with both acids and bases to form salt and water, which is what makes an oxide amphoteric.

Crown gall is caused by the bacterium Agrobacterium tumefaciens, which enters through a wound near the base, or crown, of the stem and makes the plant grow rough tumour-like swellings there.

Zinc gives hydrogen with both acids and alkalis, and it displaces copper from copper sulphate, but statement III mixes up the acids of tamarind and tomato.

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.

In the liver, methanol is oxidised to methanal (formaldehyde), which coagulates protoplasm and damages cells. Methanol, CH3OH, is the simplest alcohol and is sometimes mixed into illicit liquor.

Sulfur dioxide is made of one sulfur atom and two oxygen atoms, so its molecular mass is the sum of their atomic masses: 32 plus 2 multiplied by 16, that is 32 plus 32, which gives 64 u. Molecular mass is expressed in unified atomic mass units, written u, and…

Blood is a fluid connective tissue, with cells floating in a liquid matrix called plasma. Connective tissues link and support other parts of the body, and they have cells spread out in a matrix.

Oxygen-rich blood from the lungs returns through the pulmonary veins into the left auricle (left atrium) of the heart. The human heart has four chambers: two upper auricles (atria) that receive blood and two lower ventricles that pump it out.

Thyroxine is an iodine-containing hormone, so the thyroid gland cannot make it without iodine from the diet. The thyroid is a butterfly-shaped gland in the neck.

A balanced diet contains all the nutrients the body needs, along with roughage and water, in the right amounts. Carbohydrates and fats give energy, proteins build and repair the body, and vitamins and minerals protect against disease and keep body processes running.