Set 164 of the General Science mixed quiz has 20 multiple-choice questions from 20 different topics of the subject: Units and Measurements, Branches of Science and Their Fields of Study, Motion, Force and the Laws of Motion and more. 16 of them were asked in real previous-year papers. A topic quiz checks one chapter; this set revises the whole subject at once, the way an exam paper does, where the next question can come from any chapter. Every question carries an explanation of why the correct option is right and why the others are wrong. Keep to the timer, read the explanations at the end, and go back to the notes of any topic where you slipped.
20 questions with answers and explanations
Light year is a unit of measurement of
A light year is the distance that light travels through a vacuum in one year, so despite the word year it measures length, not time.
Read the full explanation →Ornithology is the branch of science concerned with the study of
Ornithology is the study of birds, their classification, habits, migration and nesting; Salim Ali, known as the birdman of India, was the country's best known ornithologist and wrote the Book of Indian Birds.
Read the full explanation →A car of mass 800 kg is travelling at a speed of 40 km/h on a straight road. A force of 1000 N is applied on it in the direction of its velocity for 12 s. Which one among the following is the final speed of the car?
The force gives the car an extra 15 m/s, which is 54 km/h, and 40 + 54 = 94 km/h. By Newton's second law, acceleration a = F/m = 1000 N ÷ 800 kg = 1.25 m/s².
Read the full explanation →Which one of the following statements is not correct with regard to genetically modified organisms?
Genetic modification is used in plants, animals and microbes alike, so this statement is false. A genetically modified organism is one whose DNA has been changed, usually by taking a useful gene from one organism and putting it into another.
Read the full explanation →A wooden box of mass 2 kg and dimensions (30 cm x 15 cm x 10 cm) is placed on a table with sides 30 cm and 10 cm touching the tabletop. Which one of the following is the approximate pressure exerted on the table?
Pressure is force divided by the area in contact: the weight is 2 kg × 10 m/s² = 20 N and the face touching the table is 0.30 m × 0.10 m = 0.03 m², so the pressure is 20 ÷ 0.03 ≈ 666.6 N/m².
Read the full explanation →Which of the following plant hormones is responsible for the ripening of fruits?
Ethylene is the only gaseous plant hormone, and it raises the rate of respiration in climacteric fruits such as banana, mango and tomato, so a single ripe fruit speeds up the ripening of those around it; the compound ethephon releases ethylene and is used in orchards for uniform ripening.
Read the full explanation →The mirrors used as rear-view mirrors in vehicles are
A convex mirror always forms an erect, diminished image, so it shows a much wider area of the road behind than a flat mirror of the same size, which is why it is used as a rear-view or side-view mirror.
Read the full explanation →According to which theory or law can any object with mass not travel as fast as the speed of light in empty space, that is in vacuum?
In Einstein's special theory of 1905 the energy required to accelerate a body with mass rises without limit as its speed approaches that of light, so such a body can come close to but never reach the speed of light in vacuum, which is the same for every observer.
Read the full explanation →Three resistors, R1, R2 and R3, (R1 > R2 > R3), are connected to a battery of voltage V, such that the circuit generates maximum heat per unit time. Which one among the following is the correct circuit combination for this ?
Heat produced per unit time is the power, and with a fixed battery voltage the power is P = V²/R. So the circuit gives the most heat when its total resistance is the smallest, and the smallest possible resistance comes from joining all three resistors in parallel.
Read the full explanation →In Eichler's classification, which group includes the plants that do not bear seeds?
Eichler divided the plant kingdom into two: the Cryptogamae, meaning plants with hidden reproductive organs and no seeds, which include the algae or thallophytes, the bryophytes and the pteridophytes; and the Phanerogamae, the seed bearing plants.
Read the full explanation →Isobars of elements have same :
Isobars are atoms of different elements that have the same mass number but different atomic numbers. The mass number is the total of protons and neutrons in the nucleus, so isobars have the same number of nucleons arranged differently: more protons and fewer neutrons in one, the reverse in another.
Read the full explanation →Which is the largest gland in the human body?
The liver weighs about one and a half kilograms and is both the largest gland and the largest internal organ of the body; it secretes bile, stores glycogen, iron and vitamin A, converts ammonia into urea and detoxifies drugs and poisons.
Read the full explanation →Which of the following statements are true for the reaction of Fe2O3 with aluminium? 1. It is known as the 'thermite reaction'. 2. The heat evolved is used for welding purpose. 3. Aluminium metal acts as an oxidizing agent. 4. Molten Fe and Al are formed at the end of the reaction. Select the correct answer using the code given below.
When iron(III) oxide is heated with aluminium powder, aluminium takes away the oxygen, and the reaction gives out so much heat that the iron produced is molten: Fe2O3 + 2Al → 2Fe + Al2O3 + heat.
Read the full explanation →For an ideal gas, a process is described by P = kT, where k is a constant. If the molar heat capacity for this process is C, then which one of the following is correct (where the symbols have their usual meanings)?
If pressure is proportional to temperature for a fixed amount of ideal gas, the volume must stay constant, so the process is isochoric.
Read the full explanation →Which one among the following is present in the nettle leaf hairs that causes burning pain?
The stinging hairs on nettle leaves inject methanoic acid (formic acid, HCOOH) into the skin when touched, and this acid causes the burning pain and itching.
Read the full explanation →Which of these is a bacterial disease that affects the plants?
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.
Read the full explanation →In the joining of railway tracks, iron oxide is made to react with
Railway tracks are joined by the thermite process, in which aluminium powder reduces iron oxide to molten iron. The reaction is Fe₂O₃ + 2Al → 2Fe + Al₂O₃.
Read the full explanation →Which one of the following type of medicines is used for treating indigestion?
Indigestion and heartburn are usually caused by too much acid in the stomach, and an antacid is a mild base that neutralises this extra hydrochloric acid.
Read the full explanation →Which of the following cells do not contain nucleus? 1. Root hair cells 2. Red blood cells 3. Platelets 4. Monocytes Select the correct answer using the code given below.
Mature human red blood cells and platelets have no nucleus. Red blood cells lose their nucleus as they mature in the bone marrow; this gives their biconcave disc shape more room for haemoglobin to carry oxygen, but it also means they cannot divide or repair themselves and live only about…
Read the full explanation →The mammalian heart is myogenic and it is regulated by nerves. The heartbeat originates from
The SA node, a small patch of special muscle in the wall of the right atrium, produces the electrical impulse that starts each heartbeat, which is why it is called the pacemaker of the heart.
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