Set 6 of the General Science mixed quiz has 20 multiple-choice questions from 18 different topics of the subject: Units and Measurements, Carbon and Its Compounds, Light: Reflection and Refraction and more. 19 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
The SI unit of pressure is
Pressure is force divided by area, so its unit is one newton per square metre, which is given the name pascal after Blaise Pascal.
Read the full explanation →To how many carbon atoms is each carbon atom bonded in diamond?
In diamond every carbon atom is joined to four other carbon atoms by strong covalent bonds. These bonds point towards the corners of a tetrahedron and build a rigid three-dimensional network that runs through the whole crystal.
Read the full explanation →When a beam of white light is allowed to fall on a prism, the maximum deviation of the emerging light occurs for
Violet has the shortest wavelength in visible light, so glass slows it the most and bends it the most. White light is a mix of seven colours, remembered as VIBGYOR.
Read the full explanation →Which cells in human body have no nucleus?
Mature red blood cells, or erythrocytes, lose their nucleus before they enter the blood. Losing the nucleus, and the mitochondria too, leaves more room for haemoglobin, the iron-rich protein that carries oxygen, and gives the cell its flexible biconcave disc shape, which lets it squeeze through narrow capillaries.
Read the full explanation →The elements belonging to groups _______ are known as 'd' block elements.
The d-block occupies the middle of the modern periodic table, groups 3 to 12, and its members are also called transition elements.
Read the full explanation →During expiration, air will leave the lungs when the pressure inside the lungs is
Air always moves from a region of higher pressure to one of lower pressure, so it flows out of the lungs only when the pressure inside them rises above that of the outside air.
Read the full explanation →Lime water turns milky when carbon dioxide is passed through it. It is due to the formation of:
Carbon dioxide reacts with lime water to form calcium carbonate, which does not dissolve, and its fine white particles make the water look milky.
Read the full explanation →Which one among the following hormones inhibits the growth activity in plants?
It is the main growth inhibitor among plant hormones and works against the growth promoters.
Read the full explanation →Which metal is placed at the top of the reactivity series?
The reactivity series lists metals from the most reactive to the least reactive, and potassium heads it because it loses its single outer electron most easily.
Read the full explanation →Which of the following groups of diseases consists of genetic diseases?
All three are genetic disorders, caused by changes in genes or chromosomes and passed on through birth, not by germs.
Read the full explanation →Monosodium glutamate (MSG) in food is used as
Monosodium glutamate is the sodium salt of glutamic acid, an amino acid, and it is added to soups, sauces, noodles and snacks to strengthen their savoury taste.
Read the full explanation →Mountaineers suffer nose bleeding at higher altitudes because:
At great heights the air is thin, so the atmospheric pressure acting on the body is much lower than at sea level.
Read the full explanation →If a person's kidneys stop working, his blood is filtered through an artificial kidney, otherwise he cannot survive. This process is called:
Haemodialysis uses a machine called an artificial kidney to clean the blood of a patient whose kidneys have failed.
Read the full explanation →In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?
1. Area of the hole in the lid
2. Temperature of the flame
3. Weight of the lid
The cooking temperature is set by the pressure inside the cooker, and that pressure is fixed by the weight sitting on the vent and the area of the hole under it.
Read the full explanation →Which of the following diseases is caused by the deficiency of Vitamin A?
Vitamin A, chemically retinol, is needed to make rhodopsin, the light-sensitive pigment in the rod cells of the retina that lets us see in dim light.
Read the full explanation →What is the range of audibility of human beings?
A healthy human ear can hear sound waves with frequencies from about 20 hertz to 20,000 hertz (20 kHz); this band is called the audible range.
Read the full explanation →In cataract the natural lens becomes cloudy because of change in which of the following?
The lens of the eye is made mostly of water and special proteins called crystallins, packed in a very regular order that keeps the lens clear so light can pass straight through to the retina.
Read the full explanation →The stomata open or close due to change in the
Each stoma is surrounded by two guard cells, and the pore opens or closes as these cells gain or lose water.
Read the full explanation →In the double-helix structure of human DNA, base Adenine forms two hydrogen bonds with which of the following bases to form a base-pair?
In DNA, adenine always pairs with thymine through two hydrogen bonds, and guanine pairs with cytosine through three. This is called complementary base pairing, and it is why one strand of DNA can be used to copy the other.
Read the full explanation →Which of the following devices is used to measure relatively high temperatures, such as encountered in furnaces?
A pyrometer measures very high temperatures, such as those of furnaces, kilns and molten metal, without touching the hot object.
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