Science Olympiad Model Test Paper - 1 | Science Olympiad Class 8 PDF Download

Ans: (c)

• To find the missing number, we first analyze the left pair: 343 and 7.
• Notice that 343 is equal to 7 raised to the power of 3 (7 x 7 x 7 = 343).
• Now, looking at the right pair, 729 can be expressed as 9 raised to the power of 3 (9 x 9 x 9 = 729).
• Thus, following the same pattern, the missing number is 9, which is the cube root of 729.

Ans: (d)

• The series consists of groups of three consecutive letters from the alphabet.
• ABC is followed by GHI, which skips four letters (DEF).
• Then MNO follows, skipping four letters (JKL).
• Continuing this pattern, the next group should be STU, skipping four letters (PQR).

Ans: (b)
Question figure is embedded in answer figure B.

Ans: (a)

To get the mirror image, we need to flip it horizontally.

Out of the given options, figure 1 is the only image that is horizontally flip of the image given in the question.

Ans: (c)
Answer figure C is the correct mirror image of the question figure.

Ans: (a)

• To solve this, we need to look for pairs of letters in "INTERVIEW" that have the same spacing as in the English alphabet.
• For example, the letters 'I' and 'N' are 5 letters apart in the word and also 5 letters apart in the alphabet.
• After checking all possible pairs, we find that there are only 2 such pairs that meet this criterion.
• Thus, the answer is 2 pairs.

Ans: (c)

• To decode the word HEAR, we assign each letter a numerical value based on its position in the alphabet: H=8, E=5, A=1, R=18.
• Adding these values gives us: 8 + 5 + 1 + 18 = 32.
• Then, we multiply this sum by 5 (32 x 5 = 160), which is how HEAR is coded.
• For BORN, we calculate: B=2, O=15, R=18, N=14. Adding these gives us: 2 + 15 + 18 + 14 = 49.
• Multiplying 49 by 5 results in 245 (49 x 5 = 245), which is the code for BORN.

Ans: (c)

A lizard is a type of reptile; a daisy is a type of flower. Choices 1 and 2 are incorrect because a petal and a stem are parts of a flower, not types of flowers. Choice 4 is incorrect because bud is a small growth at the tip or on the side of a stem that later develops into a flower, leaf, or branch.

Ans: (b)

• Let the total number of boys be represented as N.
• When Vinay is 10^th from the right, there are N - 10 boys to his left.
• Sunil is 15th from the left, meaning there are 15 - 1 = 14 boys to his left.
• After they switch, Vinay is now 17^th from the right, which means there are N - 17 boys to his left.
• Setting the two left counts equal gives us the equation: N - 10 = 14 + 17, leading to N = 31.

Ans: (a)

• Rashmi starts at a point and moves 4 m North.
• Then she turns West and moves 3 m.
• Next, she turns North again and walks 2 m.
• Finally, she turns East and walks 11 m.
• To find her distance from the starting point, we can visualize her path and calculate the total displacement, which results in 10 m from the starting point.

Ans: (b)
The name of the separation method is evaporation. It is the process of changing a liquid into vapours. Salt is soluble in water. So, on evaporation, water will turn to vapour while salt crystals remain in the container.

Ans: (a)
Filtration is the process in which insoluble substances from the liquid can be removed or separated by using filter paper. The liquid which is filtered is known as filtrate and the insoluble particles left in the filter paper is known as residue.

Ans: (d)
Non-metals have low densities, low melting points and are poor conductors of electricity.

Ans: (a)
In case of fires produced by electric short circuit or electric equipment, water is not used at all because water is a good conductor of electricity and may result in electric shock.

Ans: (d)
Dry leaves have low ignition temperature than heap of green leaves. So, to ignite the green leaves, we have to heat them up to ignition temperature of their constituents which is comparatively high. Hence, it is easier to ignite dry leaves than green leaves.

Ans: (b)
As outermost flame is hotter than the middle part or yellow flame, so water in beaker of Ronit will be heated in a shorter time.

Ans: (b)

Goat – Herbivores, 

Dog – Omnivores, 

Tiger – Carnivores, 

Fungi – Decomposers.

Ans: (c)

• Statement I is true because in regular reflection, such as with a smooth surface, the laws of reflection are indeed followed.
• Statement II is also true; even in irregular reflection, the laws still apply, but the reflection is scattered.
• Thus, both statements are correct, making option (c) the right choice.
• Understanding this helps clarify how light behaves on different surfaces.

Ans: (c)

• The upper fixed point of a thermometer is determined by the steam from boiling water, which is a consistent reference point.
• The lower fixed point is established using melting ice, which is also a reliable standard for temperature measurement.
• Option (c) correctly identifies these two conditions, making it the right choice.
• Other options either mix up the conditions or use incorrect terms, which do not accurately represent the calibration process.

Ans: (c)
Biosphere reserve is a large protected area which is meant for the conservation of all life forms found in a particular area. It prevents the commercial exploitation of the area.

Ans: (b)
IUCN stands for International Union for Conservation of Nature and Natural resources.

Ans: (d)

• Statement I is true as a violent tornado can indeed reach speeds of up to 300 km/h.
• Statement II is also correct because tornadoes can form within cyclones.
• Statement III accurately describes a tornado as a dark funnel-shaped cloud that extends from the sky to the ground.
• Since all three statements are correct, the answer is (d) I, II and III.

Ans: (c)

• The object starts from rest and falls due to gravity.
• During the fall, the acceleration due to gravity is constant at approximately 9.8 m/s².
• This means that the acceleration does not change; it remains the same throughout the fall.
• Thus, the correct statement is that the acceleration of the object remains same.

Ans: (b)

• The function of a fuse is to protect electrical appliances by melting when the current exceeds a certain limit, preventing damage.
• Statement I is incorrect because a fuse does not prevent current from coming out of the neutral terminal; it is designed to interrupt the circuit when necessary.
• Statement III is also incorrect as a fuse does not prevent current from the live terminal; it is meant to break the circuit in case of overload.
• Statement IV is incorrect because a fuse does not allow current to discharge to the Earth; that is the role of a grounding system.

Ans: (a)

Fish lay a large number of eggs because only a few of them, out of thousands, will be fertilised and produce a fish. This is because they are fertilised outside of the body and are highly sensitive to temperature changes and external factors including predators.

Ans: (b)

• The outermost zone of the flame is the hottest part, which is ideal for melting metals like silver and gold.
• Goldsmiths prefer this zone because it provides the necessary high temperature for effective melting.
• The middle zone and innermost zone are not as effective for this purpose.
• Thus, the correct choice is the outermost zone where the flame is hottest.

Ans: (b)

Wheat-leaf rust is a fungal disease that affects wheat. The fungus is an obligate parasite, which is capable of producing infectious urediniospores as long as infected leaf tissue remains alive.

Ans: (a)

Jams, jellies and squashes are preserved by sugar. Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food.

Ans: (b)

• The rusting of iron is a chemical and irreversible change, not physical.
• The digestion of food is correctly classified as a chemical and irreversible change.
• The transformation from woollen yarn to a knitted sweater is a physical and reversible change.

Ans: (b)

• X refers to coal, which is indeed a fossil fuel used in thermal power plants for generating electricity.
• Y describes coke, a form of carbon that is porous and primarily used in steel production.
• Z indicates coal tar, which is a complex mixture of many substances.
• Thus, the correct combination is Coal for X, Coke for Y, and Coal Tar for Z.

Ans: (a)

• Statement 1 emphasizes the importance of being cautious when dealing with strong acids and bases in a laboratory setting.
• Statement 2 explains that these substances are corrosive, can cause irritation, and are harmful to the skin.
• Since both statements are true, and statement 2 provides a valid reason for the caution mentioned in statement 1, option (a) is correct.
• Thus, it is crucial to handle strong acids and bases with care due to their dangerous properties.

Ans: (b)

• S refers to Coke, which is essential in the steel manufacturing process.
• T is Coal tar, which is used to produce naphthalene balls.
• U represents Coal gas, historically used for street lighting.
• V is LPG, commonly used as a fuel for homes and industries.

Ans: (b)

• Statement (i) is incorrect because the luminous zone is not the zone of complete combustion; it is where the flame is visible and produces light.
• Statement (ii) is correct as the dark zone is indeed the least hot part of a candle flame.
• Statement (iii) is correct because incomplete combustion occurs in the non-luminous zone, where there is less oxygen.
• Statement (iv) is incorrect; the hottest part of the candle flame is actually the luminous zone, not the non-luminous zone.

Ans: (c)

• The Rust and Smut diseases are specific types of plant diseases that affect wheat.
• These diseases are primarily caused by Fungi, which are microorganisms that can invade and damage plant tissues.
• While other options like Protozoa, Bacteria, and Algae can cause diseases, they are not responsible for Rust and Smut in wheat.
• Understanding the role of Fungi is crucial for managing and preventing these diseases in crops.

Ans: (d)

• The correct answer is Spirogyra, Sargassum, Fucus because Spirogyra is a freshwater green algae, while Sargassum and Fucus are marine brown algae.
• In the first group, Spirogyra is different from the others as it is not a marine organism.
• In the second and third groups, all organisms are marine algae.
• Thus, Spirogyra stands out as the odd one out.

Ans: (c)

• In a biosphere reserve, the manipulation zone is designed to allow for various human activities, such as agriculture and tourism, which can coexist with conservation efforts.
• The core zone is strictly protected, meaning that human activity is very limited to preserve the natural environment.
• The buffer zone serves as a transition area where some human activities are allowed, but it is not the same as the manipulation zone.
• Thus, the correct answer is that several human activities are permitted in the manipulation zone.

Ans: (d)

• All the multicellular organisms start their lives as a single cell.
• Nucleolus is situated inside the nucleus.
• Cell membrane is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space) which protects the cell from its environment.

Ans: (b)

• Plasmodium is known for reproducing through multiple fission, which is a process where the organism divides into several parts simultaneously.
• Organisms with both male and female sex organs are termed hermaphrodites, making the second blank correctly filled by this term.
• Human beings are a prime example of species that exhibit sexual dimorphism, where males and females have distinct physical differences.

Ans: (a)

• The correct answer is (a) because it includes the substances that are recognized as herbicides.
• Herbicides are chemicals used to control unwanted plants, and in this case, the options (ii) Metolachlor, (iii) Simazine, (iv) MCPA, (vii) Butachlor, (viii) 2, 4-D, and (ix) Dalapon are all effective herbicides.
• Other options contain substances that do not primarily function as herbicides, such as Malathion and Gammexane, which are insecticides.
• Thus, option (a) correctly identifies the herbicides from the list provided.

Ans: (d)

• The question asks for the mismatched pair among the options provided.
• Camels have leathery lips to help them eat tough vegetation.
• Fennec foxes are known for their large ears, which help dissipate heat.
• Macaws possess a long beak that is ideal for cracking nuts.
• However, penguins do not have adaptations for flight; instead, they are flightless birds that are adapted for swimming.

Ans: (d)

• The animals that yield wool are the Angora goat, Alpaca, Yak, Changthangi, and Merino sheep.
• Deer do not produce wool, which means they are not included in the count.
• Thus, there are a total of 5 animals that yield wool from the list provided.
• Therefore, the correct answer is 5.

Ans: (d)

• Statement (ii) is correct because the process of fertilization involves the male gamete combining with the female gamete to create an embryo.
• Statement (iv) is also correct as autogamy refers to self-fertilization, which occurs in flowers that have both male and female reproductive parts.
• Statements (i) and (iii) are incorrect; Hiptage seeds are not primarily dispersed by animals, and while maize is monoecious, it does not relate to the correct answer.
• Thus, the correct combination of statements is (ii) and (iv), making option (d) the right choice.

Ans: (b)

• Organism X is typically a type of algae, which has a cell wall and is capable of photosynthesis, while Organism Y is usually a fungus that lacks chlorophyll.
• The relationship between X and Y is beneficial for both, as X provides food through photosynthesis, and Y helps in nutrient absorption.
• Option (b) correctly describes the characteristics of X and Y in the lichen structure.
• Other options either misrepresent the nature of X and Y or provide incorrect associations.

Ans: (b)

• The organisms that undergo metamorphosis change their form during their life cycle.
• Among the options, silk moth, frog, butterfly, and cockroach are known to undergo this process.
• Snakes, hens, humans, cats, whales, and dogs do not undergo metamorphosis.
• Thus, the correct answer includes only (i), (iii), (v), and (viii), which are the silk moth, frog, butterfly, and cockroach.

Ans: (d)

Zinc gives hydrogen gas along with zinc chloride when it reacts with hydrochloric acid.

Zn + 2HCl  → ZnCl₂ + H₂

Ans: (d)

The screwdriver used by electricians while repairing electrical appliances is made of metal and metals conduct electricity. It is provided with a wooden or plastic handle because these materials are poor conductors of both heat and electricity. They insulate the body when in use and prevent electric shock. Therefore, statement I is incorrect.

Graphite, an allotrope of carbon, is a non-metal. It is a good conductor of electricity due to the presence of free electrons in its lattice. Therefore, statement II is also incorrect.

Ans: (b)

• The temperature in the lower parts of the fractional column is higher as compared to that in the upper parts. The component of mineral oil (petroleum) with a higher boiling point is collected in the lower parts of the fractional column.
• In the fractional distillation of petroleum, kerosene is collected in the lower part of the fractional column than petrol because kerosene has a higher boiling point than petrol.

Hence, both the statements I and II are correct but statement II is not the correct reason for I.

Ans: (b)

X stands for a combine machine, which can carry out both harvesting and threshing.

Ans: (c)
Wild sanctuary (X) is the area reserved for conservation of wild animals only, National park (Y) is the area reserved for conservation of both plants and animals. In this area, activities like grazing, and collection of timber are strictly prohibited. Z is biosphere reserve, which is also reserved for conservation of both plants and animals. In these areas, conservation of plants, animals and microorganisms are done along with traditional life forms, living in that area.

Ans: (b)
An endangered species is a type of organism that is threatened by extinction. These species are very likely to become extinct. Extinct species is a particular animal or plant species that can no longer be available as a wild. Vulnerable species is considered to be facing a risk of extinction in the wild.