General Science GK Questions with Answers – Page 74

Milk of magnesia is a suspension of magnesium hydroxide, a mild base that neutralises excess stomach acid without harming the body.

Energy equals power multiplied by time: 0.1 kW × 30 hours = 3 kWh, which is 3 units. The bulb's power is 100 W, which is 0.1 kW.

Chromosomes are made of DNA wound around proteins, mainly histones; together this DNA-protein material is called chromatin. In eukaryotic cells, a very long DNA molecule wraps around groups of eight histone proteins to form beads called nucleosomes.

Chlorophyll is held in the chloroplasts, the green plastids of leaf cells where photosynthesis takes place. A chloroplast is a double-membrane organelle.

When a conductor moves in a magnetic field and a current is induced in it, this rule gives the direction of that induced current.

HIV infects and destroys helper T lymphocytes, the white blood cells that coordinate the body's immune response, so immunity steadily collapses.

Cancer is uncontrolled cell division that follows the loss of the checks that normally govern growth. Normal cells divide only when signalled and stop when they touch neighbouring cells, a property called contact inhibition.

A kelvin and a degree Celsius are the same size, but the Kelvin scale starts at absolute zero, which is −273.15 °C. The kelvin is the SI unit of temperature.

Hydrogen, nitrogen, oxygen and carbon dioxide all exist as gases at about 25 °C and normal atmospheric pressure. Hydrogen boils at about −253 °C, nitrogen at −196 °C and oxygen at −183 °C, so all three are gases at room temperature.

A plane mirror always forms a virtual image, one that cannot be caught on a screen, so calling it real is the false statement.

The F2 genotypes come out as 1 TT: 2 Tt: 1 tt, so pure tall plants (TT) and short plants (tt) are equal in number.

Methanoic acid, better known as formic acid, is the acid that ants inject when they sting, which is why the bite burns.

The stinging hairs of the nettle inject methanoic acid, also called formic acid, which causes the burning pain. Nettle is a herbaceous plant whose leaves carry fine, brittle hairs.

A microphone turns sound into an electrical signal, and a speaker turns an electrical signal back into sound. Both are transducers, devices that change energy from one form to another.

Only this equation has the same number of iron, hydrogen and oxygen atoms on both sides. Iron reacts with steam to form iron(II,III) oxide and hydrogen gas.

Any particle smaller than an atom is a subatomic particle, and the muon qualifies just as the electron, proton and neutron do.

Lysosomes are membrane-bound sacs of digestive enzymes that break down foreign material such as bacteria and worn-out cell parts. Lysosomes are formed by the Golgi apparatus and contain hydrolytic enzymes that work in an acidic interior.

Lipases split fats into fatty acids and glycerol. Fat digestion happens mainly in the small intestine.

A single-celled organism has no organs at all; the one cell takes in food through its surface or by forming temporary structures.

A healthy young human ear can hear sounds with frequencies from about 20 hertz to about 20,000 hertz. Frequency is the number of vibrations per second, measured in hertz, and our ears sense it as pitch.