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All questions of Class 8 Science for CTET & State TET Exam

Which of the following tools would a farmer use to remove weeds from the field?
  • a)
    Hoe
  • b)
    Axe
  • c)
    Plough
  • d)
    Cultivator
Correct answer is option 'A'. Can you explain this answer?

Aditya Shah answered
Option A: Hoe is used to remove weeds and to loosen the soil. Hoe works like a blade. Below is the image of Hoe.
Option B: Axe is used to cut the trees.
Option C: Plough is used for tilling the soil.
Option D: The cultivator is used for ploughing.
Thus, option A is correct.
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Cutting mature crop manually or by a machine is called:
  • a)
    Irrigating
  • b)
    Harvesting
  • c)
    Breeding
  • d)
    Weeding
Correct answer is option 'B'. Can you explain this answer?

Anita Menon answered
The process of cutting the mature crop manually or by machine is called harvesting. The crops are pulled out or cut close to the ground.

Gold : metal :: Silicon : _____
a)non metal
b)metalloid
c)semi non metal
d)metal
Correct answer is option 'B'. Can you explain this answer?

Anita Menon answered
Gold is metal and Silicon is a metalloid. Those elements that shows the property of both metal and non-metal are called metalloids.

S.I. unit of pressure is
  • a)
    Celsius
  • b)
    Newton
  • c)
    Kelvin
  • d)
    Pascal
Correct answer is option 'D'. Can you explain this answer?

Saranya Nair answered
S.I. unit of pressure is Pascal. One Pascal is equal to one Newton per meter square.

From the following pick out, which is not the member of the solar system?
a)A natural satellite
b)A comet
c)An asteroid
d)A constellation
Correct answer is option 'D'. Can you explain this answer?

Aditi Saxena answered
A constellation is not the member of the solar system. These are the group of stars that forms a recognizable shape is known as Constellation.

The sun makes life possible by providing us with
  • a)
    Oxygen
  • b)
    Water
  • c)
    Heat and light
  • d)
    Carbon dioxide
Correct answer is option 'C'. Can you explain this answer?

Anita Menon answered
The Sun is the ultimate source of light and heat that support life. Life is possible on earth due to Sun. The energy required for all kinds of living organism come from Sun.

When non-metals react with water then        
  • a)
    Hydrogen gas is formed        
  • b)
    Carbon dioxide gas is formed        
  • c)
    Non-metals do not react with water        
  • d)
    None of these.
Correct answer is option 'C'. Can you explain this answer?

Amita Verma answered
Non-metals don't react with water but the non-metal oxides do react with water and they produce acids. One example is chlorine gas (chlorine oxide) reacts with clouds (water) to form acids which come down as acid rain.

The metal alloyed with gold for making jewellery :
  • a)
    copper
  • b)
    zinc
  • c)
    silver
  • d)
    aluminium
Correct answer is option 'A'. Can you explain this answer?

Sanjana Bose answered
Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. The best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead.

Which of the following microorganism promotes the formation of curd?
  • a)
    Lactobacillus
  • b)
    Amoeba
  • c)
    Spiral bacteria
  • d)
    Spirogyra
Correct answer is option 'A'. Can you explain this answer?

Amit Sharma answered
Lactobacilli are the bacteria which are naturally present in the milk that convert the sugar(lactose) into lactic acid through the process of fermentation and that is seen in the form of curd.

Can you explain the answer of this question below:

Metals are solid except :

  • A:

    mercury

  • B:

    gallium

  • C:

    sodium

  • D:

    iodine

The answer is A.

Madhurima Nair answered
All metals are found in solid state at normal room temperature except mercury, which is liquid at room temperature.

The property by which metals can be beaten into sheets is known as ___
  • a)
    Ductility
  • b)
    Lusture
  • c)
    Sonority
  • d)
    Malleability
Correct answer is option 'D'. Can you explain this answer?

Shubham Sharma answered
Malleability is a physical property of metals that defines their ability to be hammered, pressed, or rolled into thin sheets without breaking. In other words, it is the property of a metal to deform under compression and take on a new shape.

Coke contains approximately _____ carbon.
  • a)
    98 percent
  • b)
    95 percent
  • c)
    90 percent
  • d)
    99 percent
Correct answer is option 'D'. Can you explain this answer?

Ananya Das answered
Coke is obtained from destructive distillation of coal. Coke contains approximately 99% carbon. It is used in blast furnace.

Sound is produced by
  • a)
    Heating
  • b)
    Moving
  • c)
    Cooling
  • d)
    Vibration
Correct answer is option 'D'. Can you explain this answer?

Dhruv Gupta answered
Sound is produced by vibration of object. Vibration creates disturbance in medium which reaches to observer ear through air, water or solid medium.

In ancient cultures, process of separating grains from chaff is :
  • a)
    Buffering
  • b)
    Harvesting
  • c)
    Wind Winnowing
  • d)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Akshita Bose answered
Wind winnowing is an agricultural method developed by ancient cultures for separating grain from chaff. It is also used to remove hay and chaff or other pests from stored grain.

First fully synthetic fibre formed without natural material is:
  • a)
    Nylon
  • b)
    Acrylon
  • c)
    Rayon
  • d)
    Polyester
Correct answer is option 'A'. Can you explain this answer?

Isha Dey answered
Nylon
Nylon is another man-made fibre. In 1931, it was made without using any natural raw material (from plant or animal). It was prepared from coal, water and air. It was the first fully synthetic fibre.

The brightest object in clear night sky is
  • a)
    Venus
  • b)
    Sun
  • c)
    Moon
  • d)
    Star
Correct answer is option 'C'. Can you explain this answer?

Ritu Joshi answered
The answer is a.
Venus is one of the brightest objects in the night sky. Venus is so bright because its thick clouds reflect most of the sunlight that reaches it (about 70%) back into space, and because it is the closest planet to Earth.

Millions of stars together form
  • a)
    Solar system
  • b)
    Galaxy
  • c)
    Constellation
  • d)
    Comet
Correct answer is option 'B'. Can you explain this answer?

Sarita Verma answered
A Globular cluster will contain between 10,000 to several million stars. An Open cluster will contain less than a few hundred stars. A Dwarf galaxy will contain several billion stars. A Galaxy will contain tens of billions of stars.

Any plant cultivated at a large stretch of land is called :
  • a)
    crop
  • b)
    weed
  • c)
    cereal
  • d)
    fibre
Correct answer is option 'A'. Can you explain this answer?

Rohini Seth answered
When plants of the same kind are grown and cultivated in one place on large scale, it is called a crop.
Example: Crop of wheat, crop of rice, etc.

Metalloids are also known as :
  • a)
    minerals
  • b)
    semi metals
  • c)
    impure metals
  • d)
    alloys
Correct answer is option 'B'. Can you explain this answer?

Ashwin Jain answered
Metalloids, also known as semimetals are elements containing properties similar and midway between metals and nonmetals. They are found to divide the periodic table between the metals on the left and the nonmetals on the right. Metalloids often have the following properties: could be dull or shiny.

SI unit of the calorific value of a fuel is :-
a) KJ/kg
b) KW/kg
c) N/kg
d) KJ/g
Correct answer is option 'A'. Can you explain this answer?

Rohit Sharma answered
Calorific value provides the amount of energy that is released when a fuel or material undergoes the process of combustion.
It is usually a measure of energy.
The SI unit (international system of units) of calorific value is Joule/Kg or Kilo Joule/Kg.

What is the name of object through which light can pass?
  • a)
    Opaque
  • b)
    Translucent
  • c)
    Transparent
  • d)
    Luminous
Correct answer is option 'C'. Can you explain this answer?

Sanaya Shah answered
The object through which light can pass easily is called transparent object. Glass, water and thin plastic sheets are transparent object.

Which planets have huge red spot
  • a)
    Earth
  • b)
    Venus
  • c)
    Mars
  • d)
    Jupiter
Correct answer is option 'D'. Can you explain this answer?

Sounak Sengupta answered
Great Red Spot on Jupiter. The Great Red Spot is a persistent anticyclonic storm on the planet Jupiter, 22 degrees south of the equator, which has lasted at least 340 years. The storm is large enough to be visible through Earth-based telescopes.

In asexual reproduction
  • a)
    No parents are involved
  • b)
    Four parents are involved
  • c)
    One parent is involved
  • d)
    Two parents are involved
Correct answer is option 'C'. Can you explain this answer?

Disha Dey answered
In asexual reproduction only one parent is involved. The new organism is identical to parent. No gametes formation takes place in asexual reproduction.

Microorganisms are :
  • a)
    saprophytes
  • b)
    autotrophs
  • c)
    autotrophs & heterotrophs
  • d)
    hetrotrophs
Correct answer is option 'C'. Can you explain this answer?

Kavya Saxena answered
Microorganisms are either autotrophs that prepare their own food or heterotrophs that obtain their food from other organism. Autotrophic microbes includes unicellular algae, while most of bacteria and virus are heterotrophic.

Glands without ducts
  • a)
    Mammary gland
  • b)
    Exocrine gland
  • c)
    Endocrine glands
  • d)
    Pancreatic gland
Correct answer is option 'C'. Can you explain this answer?

Ananya Das answered
The glands without ducts are called ductless gland. Endocrine glands are ductless gland as they deliver the hormone to target site through blood.

The monsoon season in India is during the months:
  • a)
    April to December
  • b)
    June to September
  • c)
    November to March
  • d)
    January to May
Correct answer is option 'B'. Can you explain this answer?

Amit Sharma answered
Monsoon or rainy season, lasting from June to September. The season is dominated by the humid southwest summer monsoon, which slowly sweeps across the country beginning in late May or early June. Monsoon rains begin to recede from North India at the beginning of October. South India typically receives more rainfall.

The process of conversion of sugar into alcohol is called
  • a)
    Infection
  • b)
    Moulding
  • c)
    Nitrogen fixation
  • d)
    Fermentation
Correct answer is option 'D'. Can you explain this answer?

Aditi Saxena answered
The process of converting of sugar into alcohol is called fermentation. Ethanol Fermentation, also called Alcoholic Fermentation, is a biological process which converts sugars such as glucose, fructose and sucrose into cellular energy, producing ethanol and carbon dioxide as a side effect. As yeast performs this conversion in the absence of oxygen, alcoholic fermentation is considered an anaerobic process.

Ethanol fermentation has many uses, including the production of alcoholic beverages, the production of ethanol fuel, and bread baking.
Wine is produced by fermentation of the natural sugars present in grapes. Cider and perry are produced by similar fermentation of natural sugars in apples and pears respectively. Beer, Whiskey and vodka are produced by fermentation of grain starches that have been converted to sugar by the enzyme amylase, which is present in grain kernels that have been malted. Rum and some other beverages are produced by fermentation and distillation of sugarcane.

Which of the following is incorrect regarding plastics:
  • a)
    durable
  • b)
    non biodegradable
  • c)
    resistant to weather
  • d)
    non recyclable
Correct answer is option 'D'. Can you explain this answer?

Pooja Shah answered
Plastics are non biodegradable, resistant to weather and durable. Plastic can be recycled too. It is used to make chairs, rope, bucket and a number of other utensils.

Budding is found in
  • a)
    Bacteria
  • b)
    Protozoa
  • c)
    Planarian
  • d)
    Hydra
Correct answer is option 'D'. Can you explain this answer?

Pankaj Unni answered
Budding is a mode of asexual reproduction in which a small outgrowth develop on body surface that enlarge and get separated from parent body. Budding takes place in hydra and yeast.

Power house of the cell is :
a)mitochondria
b)chloroplast
c)ribosome
d)nucleus
Correct answer is option 'A'. Can you explain this answer?

Akshay Mehra answered
Mitochondria is called as powerhouse of the cell because it contain enzyme for cellular respiration in which energy is released in form of ATP.

The water that is purified and fit for drinking is called
a) Potable water
b) Pure water
c) Hard water
d) Saline water
Correct answer is option 'A'. Can you explain this answer?

Geetika Shah answered
The water that is purified and fit for drinking is called potable water. Portable water contains a small amount of useful salts.

A combustible substance is :-
  • a)
    wax
  • b)
    sand
  • c)
    water
  • d)
    glass
Correct answer is option 'A'. Can you explain this answer?

Malavika Basu answered
A combustible substance is one that can easily catch fire and burn when exposed to heat.
  1. Wax: It is a combustible substance because it can burn when ignited, which is why it is used in candles.
  2. Sand: It is non-combustible, meaning it cannot catch fire or burn under normal conditions.
  3. Water: It is also non-combustible, and in fact, water is commonly used to extinguish fires.
  4. Glass: It is non-combustible and does not burn; instead, it melts when subjected to very high temperatures.
Therefore, wax is the correct answer as it can burn, making it a combustible substance.

The gas which supports combustion of coal is :
  • a)
    carbon dioxide
  • b)
    oxygen
  • c)
    nitrogen
  • d)
    hydrogen
Correct answer is option 'B'. Can you explain this answer?

Ananya Das answered
Oxygen gas supports the combustion of combustible substances including coal. Combustion of coal release carbon dioxide gas as well as solid residue.

Fibre obtained by chemical treatment of wood pulp is called ___________.    
  • a)
    Natural silk
  • b)
    Rayon
  • c)
    Nylon
  • d)
    Polyester
Correct answer is option 'B'. Can you explain this answer?

Anita Menon answered
Natural Silk: The protein fibre of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons.
Rayon: Rayon is a manufactured regenerated cellulose fibre. It is made from purified cellulose, primarily from wood pulp, which is chemically converted into a soluble compound.
Nylon: Nylon is a strong, light synthetic fibre. Nylon thread is made from the polymerization of an amine and an acid chloride. 
Polyester: Polyester is a synthetic polymer made of purified terephthalic acid or its dimethyl ester dimethyl terephthalate and mono ethylene glycol. 
Hence, the correct option is B.

Which of the following is an example of contact force?
  • a)
    Muscular force
  • b)
    Gravitational force
  • c)
    Electrostatic force
  • d)
    Magnetic force
Correct answer is option 'A'. Can you explain this answer?

Kavya Chopra answered
The forces in which to bodies acting on each other are in contact are called contact force. Muscular force is an example of contact force.

Sliding friction is ______________ than static friction.
  • a)
    More
  • b)
    Equal
  • c)
    Greater
  • d)
    Less
Correct answer is option 'D'. Can you explain this answer?

Amit Sharma answered
  • Friction comes into play when irregularities present in the surfaces of two objects in contact get interlocked with each other.
  • In sliding, the time given for interlocking is very small. Hence, the interlocking is not strong.
  • Therefore, less force is required to overcome this interlocking. Because of this reason, sliding friction is less than static friction.

What is the length of vocal cords in men?
  • a)
    15mm
  • b)
    20mm
  • c)
    5mm
  • d)
    10mm
Correct answer is option 'B'. Can you explain this answer?

Amit Sharma answered
The length of the vocal chords differs in men and women, which is why there is difference in the quality of their voice. The length of the vocal chord in men is approximately 20 mm and in women it is 15 mm.

Can you explain the answer of this question below:

Pitch of sound depends upon

  • A:

    Wavelength

  • B:

    Time-period

  • C:

    Amplitude

  • D:

    Frequency

The answer is d.

Sounak Sengupta answered
The pitch of sound depends upon the frequency of the sound by the emitting source. Greater the frequency of the sound , higher will be the pitch of that sound.

Practice Quiz or MCQ (Multiple Choice Questions) with solutions are available for Practice, which would help you prepare for chapter Stars and the Solar System, Class 8, Science. You can practice these practice quizzes as per your speed and improvise the topic. 
Q.
The stars, planets, moon and objects in sky are called
  • a)
    Solar system
  • b)
    Celestial bodies
  • c)
    Natural bodies
  • d)
    Lunar bodies
Correct answer is option 'B'. Can you explain this answer?

Divya Das answered
The stars, planets, moon, and objects in the sky are called celestial bodies.

Explanation:
Celestial bodies refer to any natural objects that exist in space, such as stars, planets, moons, asteroids, comets, and galaxies. These bodies are typically observed in the night sky and have fascinated humans for centuries. Here is a breakdown of the different types of celestial bodies:

1. Stars:
Stars are massive, luminous balls of gas that emit light and heat due to nuclear reactions occurring in their cores. They are composed mostly of hydrogen and helium and are responsible for illuminating the night sky. Stars come in various sizes, colors, and brightness levels, and they exist in vast numbers throughout the universe.

2. Planets:
Planets are celestial objects that orbit around a star and do not produce their own light. In our solar system, we have eight planets, including Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Planets are typically solid or gaseous bodies and can vary significantly in size, composition, and atmospheric conditions.

3. Moon:
The moon is Earth's natural satellite, and it orbits around our planet. It is relatively small compared to planets but is still a significant celestial body. The moon reflects sunlight, allowing us to see its illuminated surface at night. It plays a crucial role in Earth's tides and has been a subject of fascination and exploration by humans.

4. Asteroids and Comets:
Asteroids are rocky objects that orbit the sun, primarily found in the asteroid belt between Mars and Jupiter. They can range in size from small rocks to larger bodies several hundred kilometers in diameter. Comets, on the other hand, are icy bodies that also orbit the sun but have a tail that forms when the sun's heat causes the comet's ices to vaporize.

5. Galaxies:
Galaxies are vast systems of stars, gas, and dust that are held together by gravity. They come in different shapes and sizes, ranging from spiral galaxies like our Milky Way to elliptical and irregular galaxies. Galaxies can contain billions or even trillions of stars and are considered the building blocks of the universe.

In conclusion, celestial bodies encompass a wide range of objects, including stars, planets, moons, asteroids, comets, and galaxies. They are awe-inspiring and play a crucial role in our understanding of the universe and our place within it.

That property of a metal by virtue of which it can be drawn into wires is 
  • a)
    malleability
  • b)
    conductivity
  • c)
    density
  • d)
    ductility
Correct answer is option 'D'. Can you explain this answer?

Ananya Das answered
The property of a metal by virtue of which metal can be drawn into thin wires is called ductility. Gold is the most ductile metal.

In most of the cases vibration of objects are not visible because
  • a)
    Wavelength is very large
  • b)
    Wavelength is very small
  • c)
    Amplitude is very small
  • d)
    Frequency is very less
Correct answer is option 'C'. Can you explain this answer?

Krisha Shah answered
The vibrations of object are not visible because in most of the cases amplitude of waves are very small. Amplitude is the maximum displacement from mean position.

A metal is characterised by :
  • a)
    non malleability
  • b)
    high electrical conductivity
  • c)
    low electrical conductivity
  • d)
    non sonorosity
Correct answer is option 'B'. Can you explain this answer?

Pooja Shah answered
Metal is characterised by high electrical conductivity. Metals are malleable, ductile, sonorous and good conductor of heat and electricity.

Chapter doubts & questions for Class 8 Science - NCERT Textbooks (Class 6 to Class 12) 2025 is part of CTET & State TET exam preparation. The chapters have been prepared according to the CTET & State TET exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for CTET & State TET 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

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